Externally stimuli-triggered spatially and temporally controlled gene delivery can play a pivotal role in achieving targeted gene delivery with maximized therapeutic efficacy. In this study, a photothermally controlled gene delivery carrier is developed by conjugating low molecular-weight branched polyethylenimine (BPEI) and reduced graphene oxide (rGO) via a hydrophilic polyethylene glycol (PEG) spacer. This PEG–BPEI–rGO nanocomposite forms a stable nano-sized complex with plasmid DNA (pDNA), as confirmed by physicochemical studies. For the in vitro gene transfection study, PEG–BPEI–rGO shows a higher gene transfection efficiency without observable cytotoxicity compared to unmodified controls in PC-3 and NIH/3T3 cells. Moreover, the PEG–BPEI–rGO nanocomposite demonstrates an enhanced gene transfection efficiency upon NIR irradiation, which is attributed to accelerated endosomal escape of polyplexes augmented by locally induced heat. The endosomal escaping effect of the nanocomposite is investigated using Bafilomycin A1, a proton sponge effect inhibitor. The developed photothermally controlled gene carrier has the potential for spatial and temporal site-specific gene delivery.

Phototriggered gene transfection is enabled by a novel nano-sized PEG–BPEI–rGO nanocomposite, developed by conjugating polymers with reduced graphene oxide (rGO) for photothermal gene transfection. This new concept of an NIR-responsive nanocomposite could provide significant insight to design the gene carriers endowed with controlled and advanced target-specific gene delivery.

Y-shaped DNA units functionalized with Ag-nanoclusters are crosslinked by nucleic acids to yield fluorescent hydrogels with controlled luminescence properties.

CeO₂/TiO₂ nanobelt heterostructures are synthesized via a cost-effective hydrothermal method. The as-prepared nanocomposites consist of CeO₂ nanoparticles assembled on the rough surface of TiO₂ nanobelts. In comparison with P25 TiO₂ colloids, surface-coarsened TiO₂ nanobelts, and CeO₂ nanoparticles, the CeO₂/TiO₂ nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture–photodegradation–release mechanism. During the photocatalytic process, MO molecules are captured by CeO₂ nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO₂/TiO₂ nanobelt heterostructures represent a new effective photocatalyst that is low-cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture–photodegradation–release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts.

The enhanced photocatalytic performance of CeO₂/TiO₂ heterostructured nanobelts is attributed to a novel capture–photodegradation–release degradation mechanism. During the photocatalytic process, MO molecules are captured by CeO₂ nanoparticles on the surface of the heterostructure, then quickly photodegraded under UV or visible light irradiation, and ultimately the degradation products are released to external environment.

In this study, it is shown that the cytotoxic response of cells as well as the uptake kinetics of nanoparticles (NPs) is cell type dependent. We use silica NPs with a diameter of 310 nm labeled with perylene dye and 304 nm unlabeled particles to evaluate cell type-dependent uptake and cytotoxicity on human vascular endothelial cells (HUVEC) and cancer cells derived from the cervix carcinoma (HeLa). Besides their size, the particles are characterized concerning homogeneity of the labeling and their zeta potential. The cellular uptake of the labeled NPs is quantified by imaging the cells via confocal microscopy in a time-dependent manner, with subsequent image analysis via a custom-made and freely available digital method, Particle_in_Cell-3D. We find that within the first 4 h of interaction, the uptake of silica NPs into the cytoplasm is up to 10 times more efficient in HUVEC than in HeLa cells. Interestingly, after 10 or 24 h of interaction, the number of intracellular particles for HeLa cells by far surpasses the one for HUVEC. Inhibitor studies show that these endothelial cells internalize 310 nm SiO₂ NPs via the clathrin-dependent pathway. Remarkably, the differences in the amount of taken up NPs are not directly reflected by the metabolic activity and membrane integrity of the individual cell types. Interaction with NPs leads to a concentration-dependent decrease in mitochondrial activity and an increase in membrane leakage for HUVEC, whereas HeLa cells show only a reduced mitochondrial activity and no membrane leakage. In addition, silica NPs lead to HUVEC cell death while HeLa cells survive. These findings indicate that HUVEC are more sensitive than HeLa cells upon silica NP exposure.

A set of experiments comparing the cytotoxicity and uptake behavior of silica nanoparticles into cells is presented. Human vascular endothelial cells (HUVEC) are more efficient in nanoparticle uptake than cervix carcinoma cells (HeLa), within the first 4 h of incubation. After 10 or 24 h, the mean number of intracellular particles for HeLa cells increases dramatically, becoming larger than the one for HUVECs. HUVECs show increased sensitivity towards silica nanoparticles when compared to HeLa cells. These results show nanotoxicity has to be assessed for each cell type individually.

Lipidic lyotropic liquid crystals are at the frontline of current research for release of target therapeutic molecules due to their unique structural complexity and the possibility of engineering stimuli-triggered release of both hydrophilic and hydrophobic molecules. One of the most suitable lipidic mesophases for the encapsulation and delivery of drugs is the reversed double diamond bicontinuous cubic phase, in which two distinct and parallel networks of ∼4 nm water channels percolate independently through the lipid bilayers, following a Pn3m space group symmetry. In the unperturbed Pn3m structure, the two sets of channels act as autonomous and non-communicating 3D transport pathways. Here, a novel type of bicontinuous cubic phase is introduced, where the presence of OmpF membrane proteins at the bilayers provides unique topological interconnectivities among the two distinct sets of water channels, enabling molecular active gating among them. By a combination of small-angle X-ray scattering, release and ion conductivity experiments, it is shown that, without altering the Pn3m space group symmetry or the water channel diameter, the newly designed perforated bicontinuous cubic phase attains transport properties well beyond those of the standard mesophase, allowing faster, sustained release of bioactive target molecules. By further exploiting the pH-mediated pore-closing response mechanism of the double amino acid half-ring architecture in the membrane protein, the pores of the perforated mesophase can be opened and closed with a pH trigger, enabling a fine modulation of the transport properties by only moderate changes in pH, which could open unexplored opportunities in the targeted delivery of bioactive compounds.

The presence of OmpF membrane proteins at the bilayers of a bicontinuous cubic phase provides unique topological interconnectivities among the two distinct sets of water channels, enabling molecular active gating between them. This newly designed perforated cubic phase attains transport properties well beyond those of the standard mesophase, allowing faster, sustained release of bioactive target molecules.

Fertilization is central to the survival and propagation of a species, however, the precise mechanisms that regulate the sperm's journey to the egg are not well understood. In nature, the sperm has to swim through the cervical mucus, akin to a microfluidic channel. Inspired by this, a simple, cost-effective microfluidic channel is designed on the same scale. The experimental results are supported by a computational model incorporating the exhaustion time of sperm.

Improving the detection of DNA hybridization is a critical issue for several challenging applications encountered in microarray and biosensor domains. Herein, it is demonstrated that hybridization between complementary single-stranded DNA (ssDNA) molecules loosely adsorbed on a mica surface can be achieved thanks to fine-tuning of the composition of the hybridization buffer. Single-molecule DNA hybridization occurs in only a few minutes upon encounters of freely diffusing complementary strands on the mica surface. Interestingly, the specific hybridization between complementary ssDNA is not altered in the presence of large amounts of nonrelated DNA. The detection of single-molecule DNA hybridization events is performed by measuring the contour length of DNA in atomic force microscopy images. Besides the advantage provided by facilitated diffusion, which promotes hybridization between probes and targets on mica, the present approach also allows the detection of single isolated DNA duplexes and thus requires a very low amount of both probe and target molecules.

Hybridization between complementary single-stranded DNA (ssDNA) molecules loosely adsorbed on a mica surface is achieved by fine-tuning the composition of the hybridization buffer. The detection of single-molecule DNA hybridization events is performed by measuring the contour length of DNA in atomic force microscopy images.

Immunoassays are used for detecting protein targets for various applications. Here, a modification of immunoassays to allow a purely electrical detection of the target protein concentration is shown. The modification comprises a β-D-glucosidase as reporter enzyme and a cyanogenic glycoside as substrate. The enzymatic reaction produces cyanide in small quantities. For electrical detection of the cyanide, a novel sensor is developed, based on a gold micro wire. The cyanide dissolves the gold wire and changes the electrical resistance of the wire. Monitoring the resistance change allows a quantitative measurement of the target human C-reactive protein (an inflammatory marker) in blood plasma in the physiological relevant concentration range.

A new electrical detection technology for immunoassays is developed based on the dissolution of a thin gold wire by cyanide. The reporter enzyme cleaves cyanogenic glycosides to form cyanide molecules. The gold leaching kinetics are monitored by measuring the electrical resistance of the wire, resulting in a quantitative detection of the target protein.

A facile and versatile method for preparing water-soluble, stable, luminescent Cu nanoclusters (NCs) via the process of size-focusing etching from nonluminescent nanocrystals is presented. Using glutathione as a model ligand, the smallest cluster, Cu₂, is selectively synthesized to form a nearly monodisperse product, eliminating the need for tedious size fractionation. Evolution of photoluminescence and absorption spectra reveal that the formation of stable cluster species occurs through surface etching. Intriguingly, the as-prepared CuNCs exhibit an aggregation-induced emission enhancement effect. The CuNCs emit a faint light when dispersed in aqueous solution, but generate a striking fluorescence intensity enhancement upon aggregation. Armed with these attractive properties, the emissive CuNCs are expected to open new opportunities for the construction of light-emitting diodes, chemosensors, and bioimaging systems.

Fluorescent Cu nanoclusters (NCs) are selectively synthesized via the surface etching route from the nonluminescent nanocrystals. Intriguingly, the as-prepared CuNCs exhibit an aggregation-induced emission enhancement effect. The CuNCs emit a faint light when dispersed in aqueous solution, but generate a striking fluorescence intensity enhancement upon aggregation.

A versatile and readily scalable approach to fabricate a cheap and sensitive paper gas sensor is described. Chemically acidified single-walled carbon nanotubes are assembled in paper, forming continuous sensing arrays with a low detection limit and high detection selectivity for ammonia gas.

Formation of heteroepitaxy and designing different-shaped heterostructured nanomaterials of metal and semiconductor in solution remains a frontier area of research. However, it is evident that the synthesis of such materials is not straightforward and needs a selective approach to retain both metal and semiconductor identities in the reaction system during heterostructure formation. Herein, the epitaxial growth of semiconductor CdSe on selected facets of metal Au seeds is reported and different shapes (flower, tetrapod, and core/shell) hetero-nanostructures are designed. These results are achieved by controlling the reaction parameters, and by changing the sequence and timing for introduction of different reactant precursors. Direct evidence of the formation of heteroepitaxy between {111} facets of Au and (0001) of wurtzite CdSe is observed during the formation of these three heterostructures. The mechanism of the evolution of these hetero-nanostructures and formation of their heteroepitaxy with the planes having minimum lattice mismatch are also discussed. This shape-control growth mechanism in hetero-nanostructures should be helpful to provide more information for establishing the fundamental study of heteroepitaxial growth for designing new nanomaterials. Such metal–semiconductor nanostructures may have great potential for nonlinear optical properties, in photovoltaic devices, and as chemical sensors.

Hetero-nanostructures in flower, tetrapod, and core/shell shapes are designed by epitaxial growth of semiconductor CdSe on Au seeds. Experimental evidence suggests that (0001) wurtzite CdSe arms preferentially grow on (111) facets of cubic Au and, depending on the reaction conditions, the nanostructures attain different shapes.

Organic field-effect transistor (OFET) memory devices made using highly stable iron-storage protein nanoparticle (NP) multilayers and pentacene semiconductor materials are introduced. These transistor memory devices have nonvolatile memory properties that cause reversible shifts in the threshold voltage (V_th) as a result of charge trapping and detrapping in the protein NP (i.e., the ferritin NP with a ferrihydrite phosphate core) gate dielectric layers rather than the metallic NP layers employed in conventional OFET memory devices. The protein NP-based OFET memory devices exhibit good programmable memory properties, namely, large memory window ΔV_th (greater than 20 V), a fast switching speed (10 μs), high ON/OFF current ratio (above 10⁴), and good electrical reliability. The memory performance of the devices is significantly enhanced by molecular-level manipulation of the protein NP layers, and various biomaterials with heme Fe^III/Fe^II redox couples similar to a ferrihydrite phosphate core are also employed as charge storage dielectrics. Furthermore, when these protein NP multilayers are deposited onto poly(ethylene naphthalate) substrates coated with an indium tin oxide gate electrode and a 50-nm-thick high-k Al₂O₃ gate dielectric layer, the approach is effectively extended to flexible protein transistor memory devices that have good electrical performance within a range of low operating voltages (<10 V) and reliable mechanical bending stability.

A novel type of transistor memory device is prepared using protein multilayers. These devices display reversible shifts in the threshold voltage as a function of charge trapping and detrapping in the protein gate dielectric layers. This approach is extended to the preparation of flexible transistor memory devices that require low operating voltages and have reliable electrical and mechanical stability.

DNA vaccination holds great potential to be a safer and more efficient alternative to traditional vaccination strategies, but the current lack of nontoxic and effective delivery systems is the greatest impediment to its clinical implementation. In this work, a convenient one-step method is used to prepare a degradable “microgel” delivery platform, featuring hydrolytic esters. Prior to hydrolysis, these micrometer-sized gel particles can effectively condense DNA due to their positive surface charge. Upon entering antigen-presenting cells (APCs), the microgels can be hydrolyzed to nontoxic zwitterionic polymers, consequently releasing the DNA and inducing phagosomal escape. Surface charge, DNA loading, cytotoxicity, and gene transfection efficiency of the hydrolysable microparticles with different tertiary to quaternary amine ratios are systematically studied. Nonhydrolysable counterparts and commercially developed PLGA-CTAB particles are used as the control. The passive targeting effect is further evaluated by blocking the phagocytosis pathway of the cells. The hydrolytic microgels prepared in this study possess great potential to become a platform for DNA vaccine delivery.

Degradable hydrogel microparticles are prepared, utilizing esters containing quaternary amines for DNA adsorption and tertiary amines for phagosomal escape. After ester hydrolysis, the particles can shift to an ultra-low-fouling and nontoxic zwitterionic form; this can additionally facilitate the release of adsorbed DNA. Due to their micrometer size, the microparticles can passively target macrophage cells but avoid entering somatic cells.

Chemical vectors as cationic polymers and cationic lipids are promising alternatives to viral vectors for gene therapy. Beside endosome escape and nuclear import, plasmid DNA (pDNA) migration in the cytosol toward the nuclear envelope is also regarded as a limiting step for efficient DNA transfection with non-viral vectors. Here, the interaction between E3-14.7K and FIP-1 to favor migration of pDNA along microtubules is exploited. E3-14.7K is an early protein of human adenoviruses that interacts via FIP-1 (Fourteen.7K Interacting Protein 1) protein with the light-chain components of the human microtubule motor protein dynein (TCTEL1). This peptide is conjugated with pDNA and mediates interaction of pDNA in vitro with isolated microtubules as well as with microtubules in cellulo. Videomicroscopy and tracking treatment of images clearly demonstrate that P79-98/pDNA conjugate exhibits a linear transport with large amplitude along microtubules upon 2 h transfection with polyplexes whereas control pDNA conjugate exhibits small non-directional movements in the cytoplasm. Remarkably, P79-98/peGFP polyplexes enhance by a factor 2.5 (up to 76%) the number of transfected cells. The results demonstrate, for the first time, that the transfection efficiency of polyplexes can be drastically increased when the microtubules migration of pDNA is facilitated by a peptide allowing pDNA docking to TCTEL1. This is a real breakthrough in the non viral gene delivery field that opens hope to build artificial viruses.

P79-98 peptide responsible for the E3-14.7K/FIP-1 interaction with microtubules is linked to a plasmid DNA to favor its cytosolic migration during cell transfection with a cationic polymer. P79-98 allows docking and transport of DNA along microtubules. P79-98/peGFP polyplexes enhance drastically the number of transfected cells. This is a real breakthrough in the non-viral gene delivery field.

In this work, a DNA inter-strand replacement strategy for therapeutic activity is successfully designed for multimodal therapy. In this multimodal therapy, chlorin e6 (Ce6) photosensitizer molecules are used for photodynamic therapy (PDT), while aptamer-AuNRs, are used for selective binding to target cancer cells and for photothermal therapy (PTT) with near infrared laser irradiation. Aptamer Sgc8, which specifically targets leukemia T cells, is conjugated to an AuNR by a thiol-Au covalent bond and then hybridized with a Ce6-labeled photosensitizer/reporter to form a DNA double helix. When target cancer cells are absent, Ce6 is quenched and shows no PDT effect. However, when target cancer cells are present, the aptamer changes structure to release Ce6 to produce singlet oxygen for PDT upon light irradiation. Importantly, by combining photosensitizer and photothermal agents, PTT/PDT dual therapy supplies a more effective therapeutic outcome than either therapeutic modality alone.

A DNA inter-strand replacement strategy for therapeutic activity is successfully designed for multimodal therapy. Chlorin e6 (Ce6) photosensitizer molecules are used for photodynamic therapy, while aptamer-AuNRs, are used for selective binding to target cancer cells and for photothermal therapy with near infrared laser irradiation. The design was effective in killing target CEM cells, without harming non-target Ramos cells.

Upconversion luminescent hollow Y₂O₃:Yb³⁺/Er³⁺ nanospheres can be synthesized by an etching-free process, which hold promising potential for applications such as drug delivery, angiography, and high-contrast cellular as well as tissue imaging, with no damage from radiation or toxicity.

Mechanized silica nanoparticles, equipped with pillar[5]arene-[2]pseudorotaxane nanovalves, operate in biological media to trap cargos within their nanopores, but release them when the pH is lowered or a competitive binding agent is added. Although cargo size plays an important role in cargo loading, cargo charge-type does not appear to have any significant influence on the amount of cargo loading or its release. These findings open up the possibility of using pillar[n]arene and its derivatives for the formation of robust and dynamic nanosystems that are capable of performing useful functions.

A scalable, low-cost and environmentally benign strategy is developed for the facile construction of a unique kind of three-dimensional porous electrode architectures for high-performance lithium ion batteries. The methodology is based on the employment of pyrolyzed bacterial cellulose as a new three-dimensional porous scaffold to support various nanostructured active electrode materials, such as SnO₂ and Ge.

A low density vertically aligned carbon nanotube-based field-emission cathode with a ballast resistor and coaxial gate is designed and fabricated. The ballast resistor can overcome the non-uniformity of the local field-enhancement factor at the emitter apex. The self-aligned fabrication process of the coaxial gate can avoid the effects of emitter tip misalignment and height non-uniformity.

Microneedles are a relatively simple, minimally invasive and painless approach to deliver drugs across the skin. However, there remain limitations with this approach because of the materials most commonly utilized for such systems. Silk protein, with tunable and biocompatibility properties, is a useful biomaterial to overcome the current limitations with microneedles. Silk devices preserve drug activity, offer superior mechanical properties and biocompatibility, can be tuned for biodegradability, and can be processed under aqueous, benign conditions. In the present work, the fabrication of dense microneedle arrays from silk with different drug release kinetics is reported. The mechanical properties of the microneedle patches are tuned by post-fabrication treatments or by loading the needles with silk microparticles, to increase capacity and mechanical strength. Drug release is further enhanced by the encapsulation of the drugs in the silk matrix and coating with a thin dissolvable drug layer. The microneedles are used on human cadaver skin and drugs are delivered successfully. The various attributes demonstrated suggest that silk-based microneedle devices can provide significant benefit as a platform material for transdermal drug delivery.

Silk is micromolded to form a high aspect ratio biomedical device for transdermal drug delivery. The device is fabricated under ambient conditions from aqueous silk solution with the ability to deliver drug into human cadaver skin. The drug release kinetics and mechanical strength of the device can be tailored for specific applications.

Multiwall carbon nanotubes (MWCNTs) have been widely used in many disciplines due to their unique physical and chemical properties, but have also raised great concerns about their possible negative health impacts, especially through occupational exposure. Although recent studies have demonstrated that MWCNTs induce granuloma formation and/or fibrotic responses in the lungs of rats or mice, their cellular and molecular mechanisms remain largely unaddressed. Here, it is reported that the TGF-β/Smad signaling pathway can be activated by MWCNTs and play a critical role in MWCNT-induced pulmonary fibrosis. Firstly, in vivo data show that spontaneously hypertensive (SH) rats administered long MWCNTs (20–50 μm) but not short MWCNTs (0.5–2 μm) exhibit increased fibroblast proliferation, collagen deposition and granuloma formation in lung tissue. Secondly, the in vivo experiments also indicate that only long MWCNTs can significantly activate macrophages and increase the production of transforming growth factor (TGF)-β1, which induces the phosphorylation of Smad2 and then the expression of collagen I/III and extracellular matrix (ECM) protease inhibitors in lung tissues. Finally, the present in vitro studies further demonstrate that the TGF-β/Smad signaling pathway is indeed necessary for the expression of collagen III in fibroblast cells. Together, these data demonstrate that MWCNTs stimulate pulmonary fibrotic responses such as fibroblast proliferation and collagen deposition in a TGF-β/Smad-dependent manner. These observations also suggest that tube length acts as an important factor in MWCNT-induced macrophage activation and subsequent TGF-β1 secretion. These in vivo and in vitro studies further highlight the potential adverse health effects that may occur following MWCNT exposure and provide a better understanding of the cellular and molecular mechanisms by which MWCNTs induce pulmonary fibrotic reactions.

Multiwall carbon nanotubes stimulate secretion of TGF-β1 in the lung by activation of alveolar macrophages, and subsequntly trigger the TGF-β/Smad signaling pathway in fibroblasts, which can upregulate the mRNA transcription of both ECM protease inhibitors and collagen type I/III.

Rapid charging and discharging supercapacitors are promising alternative energy storage systems for applications such as portable electronics and electric vehicles. Integration of pseudocapacitive metal oxides with single-structured materials has received a lot of attention recently due to their superior electrochemical performance. In order to realize high energy-density supercapacitors, a simple and scalable method is developed to fabricate a graphene/MWNT/MnO₂ nanowire (GMM) hybrid nanostructured foam, via a two-step process. The 3D few-layer graphene/MWNT (GM) architecture is grown on foamed metal foils (nickel foam) via ambient pressure chemical vapor deposition. Hydrothermally synthesized α-MnO₂ nanowires are conformally coated onto the GM foam by a simple bath deposition. The as-prepared hierarchical GMM foam yields a monographical graphene foam conformally covered with an intertwined, densely packed CNT/MnO₂ nanowire nanocomposite network. Symmetrical electrochemical capacitors (ECs) based on GMM foam electrodes show an extended operational voltage window of 1.6 V in aqueous electrolyte. A superior energy density of 391.7 Wh kg⁻¹ is obtained for the supercapacitor based on the GMM foam, which is much higher than ECs based on GM foam only (39.72 Wh kg⁻¹). A high specific capacitance (1108.79 F g⁻¹) and power density (799.84 kW kg⁻¹) are also achieved. Moreover, the great capacitance retention (97.94%) after 13 000 charge–discharge cycles and high current handability demonstrate the high stability of the electrodes of the supercapacitor. These excellent performances enable the innovative 3D hierarchical GMM foam to serve as EC electrodes, resulting in energy-storage devices with high stability and power density in neutral aqueous electrolyte.

An intertwined nanocarbon and manganese oxide hybrid foam is synthesized via coating MnO₂ nanowires onto a graphene-carbon nanotube foam (GM foam). The resulting nanoarchitecture is a monographical graphene foam conformally covered with an intertwined, densely packed nanotube/MnO₂ nanocomposite network (GMM foam). Symmetrical electrochemical capacitors based on GMM foam electrodes indicate exceptional electrochemical performance with an extended operational voltage window of 1.6 V, a high specific capacitance of 1108.79 F g⁻¹ and a power density of 799.84 kW kg⁻¹.

A series of multi-walled carbon nanotube (MWCNT) conjugates is described, functionalized with different dendrons bearing positive charges at their termini (i.e. ammonium or guanidinium groups). The dendrimeric units are anchored to the nanotube scaffolds using two orthogonal synthetic approaches, amidation and click reactions. The final nanohybrids are characterized by complementary analytical techniques, while their ability to interact with siRNA is investigated by means of agarose gel electrophoresis. The demonstration of the cell uptake capacity, the low cytotoxicity, and the ability of these cationic conjugates to silence cytotoxic genes suggests them to be promising carriers for genetic material.

Carbon nanotubes functionalized by amidation or click chemistry with dendrons of different generations possessing ammonium or guanidinium groups are synthesized and complexed to siRNA. The assessment of the cell uptake capacity, the low cytotoxicity, and the ability of these cationic conjugates to silence genes shows them to be promising carriers for genetic material.

Intramolecular junctions can be formed in single-walled carbon nanotubes (SWNTs) by introducing a pentagon and/or heptagon into the hexagonal carbon lattice. The realization of these carbon-based molecular electronics is still quite challenging. Here, we report that nickel or cobalt catalyzed etching can be applied to partially unzip an SWNT into an intermolecular junction of SWNT/graphene nanoribbon, directly confirmed by atomic force microscopy and Raman.

A fast dark-field scattering technique capturing full broadband spectra with millisecond time-resolution enables us to monitor the growth or assembly of single nano-objects in situ and in real time. Applying this technique to study the growth of single gold nanorods, together with scanning electron microscopy and finite-difference time-domain simulations, reveals precise quantitative information about gold nanorod growth kinetics.

Amyloid fibril formation is a critical step in Alzheimer's disease (AD) pathogenesis. Inhibition of Aβ aggregation has shown promising against AD and has been used in clinic trials. Here, a novel strategy is reported for the self-assembly of polyoxometalate–peptide (POM@P) hybrid particles as bifunctional Aβ inhibitors. The two-in-one bifunctional POM@P nanoparticles show an enhanced inhibition effect on amyloid aggregation in mice cerebrospinal fluid. Incorporating a clinically used Aβ fibril-staining dye, congo red (CR), into the hybrid colloidal spheres, the nanoparticles can also act as an effective fluorescent probe to monitor the inhibition process of POM@P via CR fluorescence change in real time. It is believed that such flexible organic–inorganic hybrid systems may prompt the design of new multifunctional materials for AD treatment.

A Wells–Dawson-type phosphotungstate is combined with Aβ15-20, an Aβ-targted peptide inhibitor, to assemble spherical nanoparticles. The two-in-one bifunctional POM@P nanoparticles show an enhanced targeting inhibition effect on amyloid aggregation in mice cerebrospinal fluid. Incorporating an Aβ fibril-specific staining dye into the sphere, the nanoparticle can act as a fluorescent probe to monitor the inhibition process in real time.

In the past decade, there has been significant progress in the development of water soluble near-infrared fluorochromes for use in a wide range of imaging applications. Fluorochromes with high photo and thermal stability, sensitivity, adequate pharmacological properties and absorption/emission maxima within the near infrared window (650–900 nm) are highly desired for in vivo imaging, since biological tissues show very low absorption and auto-fluorescence at this spectrum window. Taking these properties into consideration, a myriad of promising near infrared fluorescent probes has been developed recently. However, a hallmark of most of these probes is a rapid clearance in vivo, which hampers their application. It is hypothesized that encapsulation of the near infrared fluorescent dye DY-676-COOH, which undergoes fluorescence quenching at high concentrations, in the aqueous interior of liposomes will result in protection and fluorescence quenching, which upon degradation by phagocytes in vivo will lead to fluorescence activation and enable imaging of inflammation. Liposomes prepared with high concentrations of DY-676-COOH reveal strong fluorescence quenching. It is demonstrated that the non-targeted PEGylated fluorescence-activatable liposomes are taken up predominantly by phagocytosis and degraded in lysosomes. Furthermore, in zymosan-induced edema models in mice, the liposomes are taken up by monocytes and macrophages which migrate to the sites of inflammation. Opposed to free DY-676-COOH, prolonged stability and retention of liposomal-DY-676-COOH is reflected in a significant increase in fluorescence intensity of edema. Thus, protected delivery and fluorescence quenching make the DY-676-COOH-loaded liposomes a highly promising contrast agent for in vivo optical imaging of inflammatory diseases.

Liposomes encapsulated with high concentrations of a near IR fluorescent dye reveal high fluorescence quenching. These non-targeted PEGylated fluorescence-activatable liposomes lead to the release of the dye and an increase in fluorescence. In zymosan-induced edema models, the liposomes are taken up by monocytes and macrophages, which migrate to the sites of inflammation and, upon activation, enhance prolonged and reliable in vivo near IR fluorescence imaging.

The lack of an in vitro real-time osteoclast (OC) activity assay has hampered mechanistic studies of bone resorption. Such an assay is developed, employing a hydroxyapatite matrix impregnated with alkyl-capped silicon nanocrystals, which is capable of monitoring the time-course of resorption by single osteoclasts. Resorption of the matrix by OC releases the nanocrystals, which are internalized by the cell and detected as an increase in OC luminescence. This particular choice of nanocrystals is motivated by their bright pH-independent luminescence, proportional to concentration, and by their rapid uptake without cytotoxicity. In this in vitro assay, OCs are inhibited by calcitonin (CT) and methyl-β-cyclodextrin (MCD), and stimulated by receptor activator of nuclear factor kappa-B ligand (RANKL) in the expected manner. The kinetics of the assay exhibit a lag phase representing cell attachment and commencement of resorption processes, followed by a growth of cell luminescence intensity, and the whole time-course is satisfactorily described by the logistic equation.

Osteoclasts are the cells which resorb bone and are important in disease states such as osteoporosis. A real-time assay for the activty of single osteoclasts is presented. The assay utilizes luminescent silicon quantum dots in a hydroxyapatite matrix; resorption of the matrix by the cell releases the dots, which are rapidly internalized and detected by confocal fluorescence microscopy.

Photodegradation of organic pollutants in aqueous solution is a promising method for environmental purification. Photocatalysts capable of promoting this reaction are often composed of noble metal nanoparticles deposited on a semiconductor. Unfortunately, the separation of these semiconductor-metal nanopowders from the treated water is very difficult and energy consumptive, so their usefulness in practical applications is limited. Here, a precisely controlled synthesis of a large-scale and highly efficient photocatalyst composed of monolayered Au nanoparticles (AuNPs) chemically bound to vertically aligned ZnO nanorod arrays (ZNA) through a bifunctional surface molecular linker is demonstrated. Thioctic acid with sufficient steric stabilization is used as a molecular linker. High density unaggregated AuNPs bonding on entire surfaces of ZNA are successfully prepared on a conductive film/substrate, allowing easy recovery and reuse of the photocatalysts. Surprisingly, the ZNA-AuNPs heterostructures exhibit a photodegradation rate 8.1 times higher than that recorded for the bare ZNA under UV irradiation. High density AuNPs, dispersed perfectly on the ZNA surfaces, significantly improve the separation of the photogenerated electron-hole pairs, enlarge the reaction space, and consequently enhance the photocatalytic property for degradation of chemical pollutants. Photoelectron, photoluminescence and photoconductive measurements confirm the discussion on the charge carrier separation and photocatalytic experimental data. The demonstrated higher photodegradation rates demonstrated indicate that the ZNA-AuNPs heterostructures are candidates for the next-generation photocatalysts, replacing the conventional slurry photocatalysts.

The chemically conjugated hybrid system, composed of Au nanoparticles (AuNPs) and single-crystal ZnO nanorod arrays (ZNA), shows spiked club-like morphology and possesses several advantages, such as large-scale production, high fabrication efficiency, long durability, and ease of separation from reaction solution for environmental purification. Higher photodegradation rates of organic pollutants indicate that the ZNA-AuNPs are candidates for the next-generation photocatalysts, replacing the conventional slurry photocatalysts.

Aiming to highly efficient capture and analysis of circulating tumor cells, a micropillar device decorated with graphite oxide-coated magnetic nanoparticles is developed for magneto-controllable capture and release of cancer cells. Graphite oxide-coated, Fe₃O₄ magnetic nanoparticles (MNPs) are synthesized by solution mixing and functionalized with a specific antibody, following by the immobilization of such modified MNPs on our designed micropillar device. For the proof-of-concept study, a HCT116 colorectal cancer cell line is employed to exam the capture efficiency. Under magnetic field manipulation, the high density packing of antibody-modified MNPs on the micropillars increases the local concentration of antibody, as well as the topographic interactions between cancer cells and micropillar surfaces. The flow rate and the micropillar geometry are optimized by studying their effects on capture efficiency. Then, a different number of HCT116 cells spiked in two kinds of cell suspension are investigated, yielding capture efficiency >70% in culture medium and >40% in blood sample, respectively. Moreover, the captured HCT116 cells are able to be released from the micropillars with a saturated efficiency of 92.9% upon the removal of applied magnetic field and it is found that 78% of the released cancer cells are viable, making them suitable for subsequent biological analysis.

A micropillar device decorated with graphite oxide-coated magnetic nanoparticles is fabricated for magneto-controllable capture and release of cancer cells. Notably, the captured cancer cells are able to be released from the micropillars with high viability upon the removal of external magnetic field, which potentially facilitates subsequent analysis.

Targeting therapy of tumors in their early stages is crucial to increase the survival rate of cancer patients. Currently most drug-delivery systems target the neoplasia through the tumor-associated receptors overexpressed on the cancer cell membrane. However, the expression of these receptors on normal cells and tissues is inevitable, which leads to unwanted accumulation and side effects. Characteristics of the tumor microenvironment, such as acidosis, are pervasive in almost all solid tumors and can be easily accessed. It is shown that the different extracellular pH value can be used to activate/inactivate the receptor-mediated endocytosis on tumor/normal cells. This idea is implemented by conjugating a shielding molecule at the terminus of a receptor-specific ligand via a pH-sensitive hydrazone bond. The acid-activated detachment of the shielding molecule and enhanced tumor/background accumulation ratio are demonstrated. These results suggest that acid active receptor-specific peptide ligand-modified tumor-targeting delivery systems have potential use in the treatment of tumors.

To reduce or even avoid the uptake of receptor-mediated transport systems by healthy cells due to expression of receptors on normal cells, and to keep the tumor-targeting delivery efficiency, emphasis is placed on combining other tumor properties with overexpressed receptors. The design of nanoparticles (NPs) that bind with receptors only after entering the tumor acidic environment is considered. In neutral conditions, targeting ligands are shielded and internalization is not induced.

A graphene/polyaniline/poly(4-styrenesulfonate) (G/PANI/PSS)-based conducting paste is successfully fabricated by introducing a PANI/PSS nanofiller into a multilayer graphene matrix by mechanical blending. As a compatibilizer, the PSS binder increases the dispersibility, interfacial interactions, and mechanical interlocking between the multilayer graphene matrix and PANI, thereby allowing surface resistance with narrow distribution. High concentrations of this PSS binder, obtained using ex situ polymerization, further improve the adhesion of the hybrid film to a flexible substrate. The minimum surface resistance of the screen-printed G/PANI/PSS hybrid film is approximately 10 Ω sq⁻¹ for a 70 μm uniform thickness. When bent to angles of −30°, the flexible hybrid film exhibits an approximately 6% decrease in surface resistance. The surface resistance after 500 bending cycles increases by only 10 Ω sq⁻¹, which is 14 times that of smaller, graphene-based thin films. The micropatterned, screen-printed G/PANI/PSS hybrid film is evaluated as a practical dipole tag antenna. High-resolution patterns are formed in the hybrid film by the inherently high surface tension and the properties of grains within the domain-based structure. The G/PANI/PSS-based dipole tag antenna has a bandwidth of 28.7 MHz, a high transmitted power efficiency of 98.5%, and a recognition distance of 0.42 m at a mean frequency of 910 MHz. These characteristics indicate that the G/PANI/PSS-based dipole tag antenna could be used as a signal-receiving apparatus, much like a radio-frequency identification tag, for detecting nearby objects.

A graphene/polyaniline/poly(4-styrenesulfonate) (G/PANI/PSS)-based conducting paste is synthesized by mechanically mixing multilayer graphene with an aqueous solution of PANI/PSS. High concentrations of PSS are obtained, which increases the compatibility between the graphene matrix and the PANI nanofiller. This allows uniform surface resistance and good adhesion of the film to a flexible substrate. Patterned, screen-printed hybrid films are evaluated as dipole tag antennas.

An additive and template free process is developed for the facile synthesis of VO₂(B) mesocrystals via the solvothermal reaction of oxalic acid and vanadium pentoxide. The six-armed star architectures are composed of stacked nanosheets homoepitaxially oriented along the [100] crystallographic register with respect to one another, as confirmed by means of selected area electron diffraction and electron microscopy. It is proposed that the mesocrystal formation mechanism proceeds through classical as well as non-classical crystallization processes, and is possibly facilitated or promoted by the presence of a reducing/chelating agent. The synthesized VO₂(B) mesocrystals are tested as a cathodic electrode material for lithium-ion batteries, and show good capacity at discharge rates ranging from 150–1500 mA g⁻¹ and a cyclic stability of 195 mA h g⁻¹ over fifty cycles. The superb electrochemical performance of the VO₂(B) mesocrystals is attributed to the porous and oriented superstructure that ensures large surface area for redox reaction and short diffusion distances. The mesocrystalline structure ensures that all the surfaces are in intimate contact with the electrolyte, and that lithium-ion intercalation occurs uniformly throughout the entire electrode. The exposed (100) facets also lead to fast lithium intercalation, and the homoepitaxial stacking of nanosheets offers a strong inner-sheet binding force that leads to better accommodation of the strain induced during cycling, thus circumventing the capacity fading issues typically associated with VO₂(B) electrodes.

An additive and template free process is developed for the facile synthesis of VO₂(B) mesocrystals. Microscopy results demonstrate that the six-armed star architectures are composed of stacked nanosheets oriented along the [100] crystallographic register. The synthesized VO₂(B) mesocrystals are tested as a cathode material for lithium-ion batteries and show excellent capacity values at high discharge rates that are superior to non-oriented nanoparticle counterparts.

Ternary-/hetero-nanocrystals: a facile one-pot colloidal route for controlled synthesis of the ternary AgFeS₂ nanocrystals, which have a band gap of 1.21 eV, is presented for the first time. Such ternary AgFeS₂ nanocrystals can transform to Ag₂S-Fe₇S₈ heterodimers by internal thermal reaction at elevated temperature, providing a new route to synthesize semiconductor hetero-nanostructures.

Polymer grafting from graphitic carbon materials has been pursued for several decades. Unfortunately, currently available methods mostly rely on the harsh chemical treatment of graphitic carbons which causes severe degradation of chemical structure and material properties. A straightforward growth of polyaniline chain from the nitrogen (N)-doped sites of carbon nanotubes (CNTs) is presented. N-doping sites along the CNT wall nucleate the polymerization of aniline, which generates seamless hybrids consisting of polyaniline directly grafted onto the CNT walls. The resultant materials exhibit excellent synergistic electrochemical performance, and can be employed for charge collectors of supercapacitors. This approach introduces an efficient route to hybrid systems consisting of conducting polymers directly grafted from graphitic dopant sites.

An efficient route to hybrid systems of conducting polymers directly grafted from graphitic dopant sites is introduced. Nitrogen (N)-doped sites on carbon nanotubes (CNTs) initiate the polymerization of aniline, which generates hybrids consisting of polyaniline directly grafted onto the CNT walls. The resultant materials exhibit excellent electrochemical performance for charge collectors of supercapacitors.

Vertical organic thin-film transistors (VOTFTs) are promising devices to overcome the transconductance and cut-off frequency restrictions of horizontal organic thin-film transistors. The basic physical mechanisms of VOTFT operation, however, are not well understood and VOTFTs often require complex patterning techniques using self-assembly processes which impedes a future large-area production. In this contribution, high-performance vertical organic transistors comprising pentacene for p-type operation and C₆₀ for n-type operation are presented. The static current–voltage behavior as well as the fundamental scaling laws of such transistors are studied, disclosing a remarkable transistor operation with a behavior limited by injection of charge carriers. The transistors are manufactured by photolithography, in contrast to other VOTFT concepts using self-assembled source electrodes. Fluorinated photoresist and solvent compounds allow for photolithographical patterning directly and strongly onto the organic materials, simplifying the fabrication protocol and making VOTFTs a prospective candidate for future high-performance applications of organic transistors.

A novel architecture for high performance vertical organic transistors is presented. Using C60 and pentacene, an n- and p-type transistor operation in these devices possessing a channel length of <100 μm is obtained. High transconductance values combined with the advantage of photolithographic integration will allow them to surpass the performance restrictions of planar transistor concepts.

A novel composite, MoS₂-coated three-dimensional graphene network (3DGN), referred to as MoS₂/3DGN, is synthesized by a facile CVD method. The 3DGN, composed of interconnected graphene sheets, not only serves as template for the deposition of MoS₂, but also provides good electrical contact between the current collector and deposited MoS₂. As a proof of concept, the MoS₂/3DGN composite, used as an anode material for lithium-ion batteries, shows excellent electrochemical performance, which exhibits reversible capacities of 877 and 665 mAh g⁻¹ during the 50^th cycle at current densities of 100 and 500 mA g⁻¹, respectively, indicating its good cycling performance. Furthermore, the MoS₂/3DGN composite also shows excellent high-current-density performance, e.g., depicts a 10^th-cycle capacity of 466 mAh g⁻¹ at a high current density of 4 A g⁻¹.

A high-performance anode material for lithium-ion batteries is prepared based on the MoS₂-coated three-dimensional graphene network (3DGN), which is prepared via a facile CVD method for deposition of MoS₂ on the surface of 3DGN. This novel material might be also useful in other clean energy applications, such as electrocatalytic hydrogen production.

The understanding and control of nanoparticle transport into and through cellular compartments is central to biomedical applications of nanotechnology. Here, it is shown that the transport pathway of 50 nm polystyrene nanoparticles decorated with vitamin B₁₂ in epithelial cells is different compared to both soluble B₁₂ ligand and unmodified nanoparticles, and this is not attributable to B₁₂ recognition alone. Importantly, the study indicates that vitamin B₁₂-conjugated nanoparticles circumnavigate the lysosomal compartment, the destination of soluble vitamin B₁₂ ligand. Whereas cellular trafficking of soluble B₁₂ is confirmed to occur via the clathrin-mediated pathway, transport of B₁₂-conjugated nanoparticles appears to predominantly take place by a route that is perturbed by caveolae-specific inhibitors. This data suggests that, following its conjugation to nanoparticles, in addition to dramatically increasing the cellular uptake of nanoparticles, the normal cell trafficking of B₁₂ is switched to an alternative pathway, omitting the lysosomal stage: a result with important implications for oral delivery of nanoparticulate diagnostics and therapeutics.

The transport pathway of vitamin B₁₂-conjugated nanoparticles in an intestinal cell model is shown to be different to both soluble B₁₂ and unmodified nanoparticles. Following its conjugation to nanoparticles, B₁₂ trafficking is switched to an alternative pathway, omitting the lysosomal stage. Unlike soluble B₁₂, the uptake of vitamin B₁₂-bearing nanoparticles occurs by a route perturbed by caveolae-specific inhibitors.

A simple and low-energy-consuming approach to synthesize highly stable and dispersive silver nanoparticle–graphene (AgNP–GE) nanocomposites has been developed, in which the stability and dispersivity of the composites are varied greatly with the pH value and temperature of the reaction. The results demonstrate that the optimal reaction conditions are pH 11 at room temperature for 70 min. As-synthesized composites display excellent antimicrobial activity, and can completely inhibit the growth of Escherichia coli cells at a concentration of 20 mg L⁻¹ (20 ppm). After treatment with 10 ppm AgNP–GE composites, the cells are killed completely within 3 h. The unique structure imparts such good antimicrobial properties to the composites. Firstly, the sheetlike AgNP–GE tends to be adsorbed and accumulated onto the surface of cells, which can change the permeability and enhance the antimicrobial activity. Secondly, Ag⁺ released from AgNPs can act on the cells effectively and fully, thereby resulting in cell death.

The unique structure of silver nanoparticle–graphene (AgNP–GE) nanocomposites gives them excellent antimicrobial properties. First, the sheetlike AgNP–GE are adsorbed and accumulated on the surface of cells through electrostatic attraction, which changes the permeability and enhances the antimicrobial activity. Second, Ag⁺ ions released from AgNPs act on the cells effectively and fully, thereby resulting in cell death.

A combined experimental and theoretical investigation is carried out into the electrical transport across a fullerene dumbbell one-molecule junction. The newly designed molecule comprises two C₆₀s connected to a fluorene backbone via cyclopropyl groups. It is wired between gold electrodes under ambient conditions by pressing the tip of a scanning tunnelling microscope (STM) onto one of the C₆₀ groups. The STM allows us to identify a single molecule before the junction is formed through imaging, which means unambiguously that only one molecule is wired. Once lifted, the same molecule could be wired many times as it was strongly fixed to the tip, and a high conductance state close to 10⁻² G₀ is found. The results also suggest that the relative conductance fluctuations are low as a result of the low mobility of the molecule. Theoretical analysis indicates that the molecule is connected directly to one electrode through the central fluorene, and that to bind it to the gold fully it has to be pushed through a layer of adsorbates naturally present in the experiment.

The conductance versus distance behavior of a single C₆₀ dumbbell molecule trapped between two gold electrodes is reported. The presence of only one molecule in the junction is unambiguously identified by prior imaging. The current flows directly into the centre of the molecule, whilst random conductance fluctuations are kept low thanks to the low mobility of the molecule.

Cross-linked rather than non-covalently bonded graphitic carbon nitride (g-C₃N₄)/reduced graphene oxide (rGO) nanocomposites with tunable band structures have been successfully fabricated by thermal treatment of a mixture of cyanamide and graphene oxide with different weight ratios. The experimental results indicate that compared to pure g-C₃N₄, the fabricated CN/rGO nanocomposites show narrowed bandgaps with an increased in the rGO ratio. Furthermore, the band structure of the CN/rGO nanocomposites can be readily tuned by simply controlling the weight ratio of the rGO. It is found that an appropriate rGO ratio in nanocomposite leads to a noticeable positively shifted valence band edge potential, meaning an increased oxidation power. The tunable band structure of the CN/rGO nanocomposites can be ascribed to the formation of C−O−C covalent bonding between the rGO and g-C₃N₄ layers, which is experimentally confirmed by Fourier transform infrared (FT-IR) and X-ray photoelectron (XPS) data. The resulting nanocomposites are evaluated as photocatalysts by photocatalytic degradation of rhodamine B (RhB) and 4-nitrophenol under visible light irradiation (λ > 400 nm). The results demonstrate that the photocatalytic activities of the CN/rGO nanocomposites are strongly influenced by rGO ratio. With a rGO ratio of 2.5%, the CN/rGO-2.5% nanocomposite exhibits the highest photocatalytic efficiency, which is almost 3.0 and 2.7 times that of pure g-C₃N₄ toward photocatalytic degradation of RhB and 4-nitrophenol, respectively. This improved photocatalytic activity could be attributed to the improved visible light utilization, oxidation power, and electron transport property, due to the significantly narrowed bandgap, positively shifted valence band-edge potential, and enhanced electronic conductivity.

Tunable optical properties of g-C₃N₄/reduced graphene oxide (rGO) nanocomposite improve the visible light utilization, oxidation power, and electron transport property, resulting in a dramatically enhanced visible light photocatalytic activity at the appropriate rGO ratio.

Stretchable conductors, which can keep their excellent electrical conductivity while highly stretched, have been investigated extensively due to their wide range of applications in flexible and stretchable electronics, wearable displays, etc.; however, their preparation is often complicated and expensive. Herein, an efficient method to prepare high performance stretchable conductors through morphological control of conductive networks formed with carbon nanotubes (CNTs) in an elastomer matrix is reported. It is observed that an interface-mediated method could be used to align randomly oriented filler during stretching and to induce buckling of CNTs during relaxation. Further morphological studies indicate the possible formation of a wavy CNT structure induced by cyclic pre-straining. Subsequent thermal annealing is observed to collapse the oriented network and improve the local contacts between conductive networks. Through such a simple procedure, a conductivity of nearly 1000 S m⁻¹ and a stretchability of 200% can be achieved for composites containing 20 wt% CNTs. CNTs are observed to buckle over a large area in polymer bulk, and the combination of pre-straining and thermal annealing modifies the conductive network in the elastomer matrix. As a general method, this could be used for easy fabrication of high-performance stretchable conductors for arbitrary-shaped objects on a large scale.

High-performance, stretchable conductors can be fabricated through a simple and efficient method using a combination of pre-straining and subsequent thermal annealing. It is observed that straining can induce orientation and relaxation, and that annealing can trigger bulking of multi-walled carbon nanotubes (MWNTs). Through such procedures, conductive polymer composites based on elastomers containing 20 wt% MWNTs can achieve a conductivity of 1000 S m^–1 and a strechability of 200%.

Nanocarriers are a new type of nonviral gene carriers, many of which have demonstrated a broad range of pharmacological and biological properties, such as being biodegradable in the body, stimulus-responsive towards the surrounding environment, and an abiltiy to specifically targeting certain disease sites. By summarizing some main types of nanocarriers, this Concept considers the current status and possible future directions of the potential clinical applications of multifunctional nanocarriers, with primary attention on the combination of such properties as biodegradability, targetability, transfection ability, and stimuli sensitivity.

General concepts in the development of nanoparticle-based carriers for gene delivery systems are summarized. This concept highlights the current status and possible future directions of gene delivery, with a particular emphasis on the clinical application of multifunctional nanocarriers on the combination of such properties as biodegradability, targetability, transfection ability, and stimuli sensitivity.

Helical carbon nanotubes with intentionally incorporated non-hexagonal defects have unexpectedly high toughness and plasticity, in addition to the well-recognized extreme elasticity. The obtained toughness approaches 5000 J g⁻¹ with decreasing spring radius. The high toughness originates from the plastic nanohinge formation as a result of distributed partial fractures. A strong spring size effect, contradictory to the continuum solution, is precisely described by an atomistic bond-breaking model.

The natural ability of Bacillus sp. to adapt to nanosilver cytotoxicity upon prolonged exposure is reported for the first time. The combined adaptive effects of nanosilver resistance and enhanced growth are induced under various intensities of nanosilver-stimulated cellular oxidative stress, ranging from only minimal cellular redox imbalance to the lethal levels of cellular ROS stimulation. An important implication of the present work is that such adaptive effects lead to the ultimate domination of nanosilver-resistant Bacillus sp. in the microbiota, to which nanosilver cytotoxicity is continuously applied.

A continuous and wide range control of the diameter (1.9−3.2 nm) and density (0.03−0.11 g cm⁻³) of single-walled carbon nanotube (SWNT) forests is demonstrated by decoupling the catalyst formation and SWNT growth processes. Specifically, by managing the catalyst formation temperature and H₂ exposure, the redistribution of the Fe catalyst thin film into nanoparticles is controlled while a fixed growth condition preserved the growth yield. The diameter and density are inversely correlated, where low/high density forests would consist of large/small diameter SWNTs, which is proposed as a general rule for the structural control of SWNT forests. The catalyst formation process is modeled by considering the competing processes, Ostwald ripening, and subsurface diffusion, where the dominant mechanism is found to be Ostwald ripening. Specifically, H₂ exposure increases catalyst surface energy and decreases diameter, while increased temperature leads to increased diffusion on the surface and an increase in diameter.

A continuous and wide range control of the diameter of single-walled carbon nanotube (SWNT) forests is demonstrated by decoupling the catalyst formation and SWNT growth processes. The diameter and density are inversely correlated, where low/high density forests would consist of large/small diameter SWNTs, which is proposed as a general rule. The model for the catalyst formation process shows that the dominant mechanism is Ostwald ripening.

A highly emissive far-red/near-infrared (FR/NIR) fluorescent conjugated polymer (CP), poly[(9,9-dihexylfluorene)-co-2,1,3-benzothiadiazole-co-4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole] (PFBTDBT10) is designed and synthesized via Suzuki polymerization. Formulation of PFBTDBT10 using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG₂₀₀₀) and DSPE-PEG₅₀₀₀-folate as the encapsulation matrix yielded CP-loaded DSPE-PEG-folic acid nanoparticles (CPDP-FA NPs) with bright FR/NIR fluorescence (27% quantum yield) and a large Stoke's shift of 233 nm in aqueous solution. CPDP-FA NPs show improved thermal/photostabilities and larger Stoke's shifts as compared to commercially available quantum dots (Qdot 655) and organic dyes such as Alexa Fluor 555 and Rhodamine 6G. In vivo studies of CPDP-FA NPs on a hepatoma H22 tumor-bearing mouse model reveal that they could serve as an efficient FR/NIR fluorescent probe for targeted in vivo fluorescence imaging and cancer detection in a high contrast and specific manner. Together with the negligible in vivo toxicity, CPDP-FA NPs are promising FR/NIR fluorescent probes for future in vivo applications.

Bright far-red/near-infrared conjugated polymer nanoparticles with surface folate ligand and 27% quantum yield in aqueous media are synthesized via a one-step lipid-PEG-folate formulation. The obtained nanoparticles show good thermal/photostabilities and a large Stoke's shift, which compare favorably with commercially available quantum dots (Qdot 655) and organic dyes (Alexa Fluor 555 and Rhodamine 6G), making them a safe and efficient FR/NIR fluorescent probe for targeted in vivo fluorescence imaging and cancer detection in a high contrast and specific manner.

Immunization to the model protein antigen ovalbumin (OVA) is investigated using MCM-41 mesoporous silica nanoparticles as a novel vaccine delivery vehicle and adjuvant system in mice. The effects of amino surface functionalization and adsorption time on OVA adsorption to nanoparticles are assessed. Amino-functionalized MCM-41 (AM-41) shows an effect on the amount of OVA binding, with 2.5-fold increase in binding capacity (72 mg OVA/g AM-41) compared to nonfunctionalized MCM-41 (29 mg OVA/g MCM-41). Immunization studies in mice with a 10 μg dose of OVA adsorbed to AM-41 elicits both antibody and cell-mediated immune responses following three subcutaneous injections. Immunizations at a lower 2 μg dose of OVA adsorbed to AM-41 particles results in an antibody response but not cell-mediated immunity. The level of antibody responses following immunization with nanoformulations containing either 2 μg or 10 μg of OVA are only slightly lower than that in mice which receive 50 μg OVA adjuvanted with QuilA, a crude mixture of saponins extracted from the bark of the Quillaja saponaria Molina tree. This is a significant result, since it demonstrates that AM-41 nanoparticles are self-adjuvanting and elicit immune responses at reduced antigen doses in vivo compared to a conventional delivery system. Importantly, there are no local or systemic negative effects in animals injected with AM-41. Histopathological studies of a range of tissue organs show no changes in histopathology of the animals receiving nanoparticles over a six week period. These results establish the biocompatible MCM-41 silica nanoparticles as a new method for vaccine delivery which incorporates a self-adjuvant effect.

Amino-functionalized mesoporous silica nanoparticles have a high adsorption capacity for ovalbumin. Ovalbumin-bound nanoparticles are used as a delivery system in mice to test their efficacy. Immunization results in both cell-mediated and humoral immunity. The nanoparticles not only act as a protein carrier but also as an effective adjuvant. These results establish mesoporous silica nanoparticles as a viable vaccine delivery vehicle.

Reduced graphene oxide nanomesh (rGONM), as one of the recent structures of graphene with a surprisingly strong near-infrared (NIR) absorption, is used for achieving ultraefficient photothermal therapy. First, by using TiO₂ nanoparticles, graphene oxide nanoplatelets (GONPs) are transformed into GONMs through photocatalytic degradation. Then rGONMs functionalized by polyethylene glycol (PEG), arginine–glycine–aspartic acid (RGD)-based peptide, and cyanine 7 (Cy7) are utilized for in vivo tumor targeting and fluorescence imaging of human glioblastoma U87MG tumors having α_νβ₃ integrin receptors, in mouse models. The rGONM-PEG suspension (1 μg mL⁻¹) exhibits about 4.2- and 22.4-fold higher NIR absorption at 808 nm than rGONP-PEG and graphene oxide (GO) with lateral dimensions of ≈60 nm and ≈2 μm. In vivo fluorescence imaging demonstrates high selective tumor uptake of rGONM-PEG-Cy7-RGD in mice bearing U87MG cells. The excellent NIR absorbance and tumor targeting of rGONM-PEG-Cy7-RGD results in an ultraefficient photothermal therapy (100% tumor elimination 48 h after intravenous injection of an ultralow concentration (10 μg mL⁻¹) of rGONM-PEG-Cy7-RGD followed by irradiation with an ultralow laser power (0.1 W cm⁻²) for 7 min), whereas the corresponding rGO- and rGONP-based composites do not present remarkable treatments under the same conditions. All the mice treated by rGONM-PEG-Cy7-RGD survived over 100 days, whereas the mice treated by other usual rGO-based composites were dead before 38 days. The results introduce rGONM as one of the most promising nanomaterials in developing highly desired ultraefficient photothermal therapy.

Reduced graphene oxide nanomesh (rGONM) functionalized by polyethylene glycol (PEG), arginine–glycine–aspartic acid (RGD)-based peptide, and cyanine 7 (Cy7) is utilized for in vivo tumor targeting and fluorescence imaging of human glioblastoma tumors in mice. Simultaneous application of an ultralow concentration of injected rGO-based composite and an ultralow near-infrared (NIR) laser power provide tumor ablation with 100% efficiency.

An experimental model is introduced for the induction of endothelial cell (EC) tubulogenesis after 24 h of incubation on micropatterned polymer surfaces. Pericytes or mesenchymal stem cells are added separately to this system to evaluate their effect on tubular stabilization. In the absence of additional cells, the tubular structures are lost after 36 h. Addition of only pericytes, however, stabilizes the EC vasculogenic tubes.

A strategy for the regulation of enzyme cascade reaction efficiency by a DNA machine in vitro is presented. Two cascade enzymes (GOx and HRP) are attached to the DNA machine, and the enzyme cascade reaction shows much higher efficiency when the two enzymes are brought closer by the DNA machine than when they are distant.

Several single-stranded scaffold DNA, obtained from rolling circle amplification (RCA), are folded by different staples to form DNA nanoribbons. These DNA nanoribbons are rigid, simple to design, and cost-effective drug carriers, which are readily internalized by mammalian cells and show enhanced immunostimulatory activity.

Polysilsesquioxane (PSQ) nanoparticles are crosslinked homopolymers formed by condensation of functionalized trialkoxysilanes, and provide an interesting platform for developing biologically and biomedically relevant nanomaterials. In this work, the design and synthesis of biodegradable PSQ particles with extremely high payloads of paramagnetic Gd(III) centers is explored, for use as efficient contrast agents for magnetic resonance imaging (MRI). Two new bis(trialkoxysilyl) derivatives of Gd(III) diethylenetriamine pentaacetate (Gd-DTPA) containing disulfide linkages are synthesized and used to form biodegradable Gd-PSQ particles by base-catalyzed condensation reactions in reverse microemulsions. The Gd-PSQ particles, PSQ-1 and PSQ-2, carry 53.8 wt% and 49.3 wt% of Gd-DTPA derivatives, respectively. In addition, the surface carboxy groups on the PSQ-2 particles can be modified with polyethylene glycol (PEG) and the anisamide (AA) ligand to enhance biocompatibility and cell uptake, respectively. The Gd-PSQ particles are readily degradable to release the constituent Gd(III) chelates in the presence of endogenous reducing agents such as cysteine and glutathione. The MR relaxivities of the Gd-PSQ particles are determined using a 3T MR scanner, with r₁ values ranging from 5.9 to 17.8 mMs⁻¹ on a per-Gd basis. Finally, the high sensitivity of the Gd-PSQ particles as T₁-weighted MR contrast agents is demonstrated with in vitro MR imaging of human lung and pancreatic cancer cells. The enhanced efficiency of the anisamide-functionalized PSQ-2 particles as a contrast agent is corroborated by both confocal laser scanning microscopy imaging and ICP-MS analysis of Gd content in vitro.

The applicability of polysilsesquioxane (PSQ) nanoparticles with cleavable Gd chelates as T₁-weighted MRI contrast agents is evaluated in vitro. The chelates are covalently linked via a redox-responsive disulfide moiety, and the platform is further functionalized to improve biocompatibility and cell uptake. The Gd-PSQ particles show high r₁ relaxivity values and strong enhancement of T₁-weighted images of human lung and pancreatic cancer cells in vitro.

The atomic force microscope (AFM) has become integrated into standard characterisation procedures in many different areas of research. Nonetheless, typical imaging rates of commercial microscopes are still very slow, much to the frustration of the user. Developments in instrumentation for “high-speed AFM” (HSAFM) have been ongoing since the 1990s, and now nanometer resolution imaging at video rate is readily achievable. Despite thorough investigation of samples of a biological nature, use of HSAFM instruments to image samples of interest to materials scientists, or to carry out AFM lithography, has been minimal. This review gives a summary of different approaches to and advances in the development of high-speed AFMs, highlights important discoveries made with new instruments, and briefly discusses new possibilities for HSAFM in materials science.

Developments in instrumentation for “high-speed AFM” (HSAFM) have been ongoing since the 1990s, and now nanometer resolution imaging and lithography at video rate is readily achievable. This review provides a summary of different approaches to and advances in the development of high-speed AFMs, highlights important discoveries made with new instruments, and discusses new possibilities for HSAFM in materials science.

Nanotechnology has often been applied in the development of targeted drug-delivery systems for the treatment of cancer. An ideal nanoscale system for drug delivery should be able to selectively deliver and rapidly release the carried therapeutic drug(s) in cancer cells and, more importantly, not react to off-target cells so as to eliminate unwanted toxicity on normal tissues. To reach this goal, a selective chemotherapeutic is formulated using a hollow gold nanosphere (HAuNS) equipped with a biomarker-specific aptamer (Apt), and loaded with the chemotherapy drug doxorubicin (DOX). The formed Apt-HAuNS-Dox, approximately 42 nm in diameter, specifically binds to lymphoma tumor cells and does not react to control cells that do not express the biomarker. Through aptamer-mediated selective cell binding, the Apt-HAuNS-Dox is internalized exclusively into the targeted tumor cells, and then released the DOX intracellularly. Of note, although the formed Apt-HAuNS-Dox is stable under normal biological conditions (pH 7.4), it appears ultrasensitive to pH change and rapidly releases 80% of the loaded DOX within 2 h at pH 5.0, a condition seen in cell lysosomes. Functional assays using cell mixtures show that the Apt-HAuNS-Dox selectively kills lymphoma tumor cells, but has no effect on the growth of the off-target cells in the same cultures, indicating that this ultra pH-sensitive Apt-HAuNS-Dox can selectively treat cancer through specific aptamer guidance, and will have minimal side effects on normal tissue.

Using aptamer technology, an innovative ultra pH-sensitive nanoscale drug-delivery system is developed that selectively kills lymphoma tumor cells with no effects on off-target cells. The successful in vitro tests reported here represent an important step in the development of next-generation targeted cancer therapeutics.

Self-assembly of ZnO porous nanosheets with novel parallelogram morphology and high specific surface area is achieved by a one-pot alkalization reaction. The growth mechanism relies on the dual roles of the precursor: providing the building blocks and the assembling template concurrently. This porous structure with active surface defects serves as a high-performance semiconductor substrate for surface-enhanced Raman scattering (SERS).

The false-color (3D type) image of the intensity of the Raman spectra of monolayer MoS₂ versus both peak positions and polar angles is plotted. It shows that the strongest E_2g¹⁺ and E_2g¹⁻ peaks appear at different angles, reflected as the alternation of the maxima of the intensity within the frequency range of the E_2g¹ mode, which is the consequence of the crystallographic orientation relevant to the strain direction as predicted by theoretical analysis.

ZnO@Zn₃P₂ quantum dots (QDs) are synthesized, with emission from yellow to red. Photoelectrochemical investigations reveal that the current and voltage of the QD-derivatized electrodes show a response upon illumination. A photocurrent of ca. 8 nA cm⁻² for a monolayer of ZnO@Zn₃P₂ QDs deposited on indium tin oxide (ITO) electrode is recorded.

Blue, pink, and yellow colorations appear from twisted bi-layer graphene (tBLG) when transferred to a SiO₂/Si substrate (SiO₂ = 100 nm-thick). Raman and electron microscope studies reveal that these colorations appear for twist angles in the 9–15° range. Optical contrast simulations confirm that the observed colorations are related to the angle-dependent electronic properties of tBLG combined with the reflection that results from the layered structure tBLG/100 nm-thick SiO₂/Si.

A facile and general method is reported to prepare ordered porous graphene-based binder-free electrodes on a large scale. This preparation process allows the easy adjustment of the selected components, weight ratio of componets, and the thickness of the electrodes. Such ordered porous electrodes demonstrate superior Li storage properties; for example, graphene–Fe₃O₄@C depicts high capacities of 1123.8 and 505 mAh g⁻¹ at current densities of 0.5 and 10 A g⁻¹, respectively.

An aptamer-linked graphene oxide (GO) microarray is synthesized for multiplex heavy metal ion detection. Fluorescent nanosized GO sheets are micropatterned, and specific aptamers targeting Ag⁺ and Hg²⁺ are immobilized on the GO array. Upon capture of the target heavy metal ions, electron transfer occurs between the GO (donors) and the heavy metal ions (acceptors), leading to fluorescence quenching of the GO.

The combined use of ZnO, Mg, MgO, and silk provides routes to classes of thin-film transistors and mechanical energy harvesters that are soluble in water and biofluids. Experimental and theoretical studies of the operational aspects and dissolution properties of this type of transient electronics technology illustrate its various capabilities. Application opportunities range from resorbable biomedical implants, to environmentally dissolvable sensors, and degradable consumer electronics.

On-demand degradable polymer particles are fabricated via electrospraying of a solution of acetal-protected dextran that further includes 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine as a photoacid generator. The illumination of UV light gives rise to photoacid and activates the catalytic deprotection of hydroxyl groups of dextran, leading to controlled dissolution of the microparticles in water.

A strategy for attomolar-level detection of small molecule-size proteins is reported based on Rayleigh light scattering spectroscopy of individual nanoplasmonic aptasensors by exploiting the outstanding characteristics of gold colloids to amplify the nontransparent resonant signal at ultralow analyte concentrations. The fabrication method utilizes thiol-mediated adsorption of a DNA aptamer on the immobilized Au nanoparticle surface, the interfacial binding characteristics of the aptamer with its target molecules, and the antibody–antigen interaction through plasmonic resonance coupling of the Au nanoparticles. Using lysozyme as a model analyte for disease detection, the detection limit of the aptasensor is ∼7 × 10³ aM, corresponding to the LSPR λ_max shift of ∼2.25 nm. Up to a 380% increase in the localized resonant λ_max shift is demonstrated upon antibody binding to the analyte compared to the primary response during signal amplification using immunogold colloids. This enhancement leads to a limit of detection of ∼7 aM, which is an improvement of three orders of magnitude. The results demonstrate substantial promise for developing coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes.

An individual aptasensor is effectively exploited to detect disease utilizing thiol-mediated adsorption of the DNA aptamer, the interfacial binding characteristics of the aptamer with its target, and the antibody-antigen interaction through plasmon coupling of the nanoparticles. Up to a 380% increase in the LSPR λ_max shift is demonstrated compared to an unenhanced shift using immunogold as the resonant label. This leads to a detection limit of ∼7 aM.

Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized.

Techniques used for interconnection formation, which is crucial for nanodevice performance, are categorized into two types. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, contact resistances are compared and the electrodeposition approach is emphasized.

Plasmonic metal/semiconductor nanocomposites promise to be a breakthrough for boosting and investigating photon-assisted processes at the nanoscale, with exciting perspectives for energy conversion and catalysis. However, the efficiency and selectivity of these surface processes are still far from being controlled. Here, shown for the first time, is a new class of photocatalyst which is based on the synergistic combination of bowtie-like gold nanoantennas and SiO₂/TiO₂ core/shell oxide beads. These systems are exploited as efficient near-field optical light concentrators, stimulating photon-driven processes at the metal-semiconductor interface. Extraordinary enhancements of photodegradation rates (minutes instead of hours) result from matching the nanoantenna surface plasmon resonance with the optical absorption of organic dyes and the excitation source wavelength. Moreover, strong Raman enhancements are observed allowing for direct in-situ monitoring of reaction progress of different analytes on the same site.

Au bowtie-like nanoantennas are fabricated on SiO₂/TiO₂ core/shell photocatalytic beads and exploited to concentrate light in order to promote degradation reactions. Surface-enhanced Raman scattering allows direct in-situ monitoring of the reaction progress of different analytes at the same site.

A simple method for the formation of multiscale metal patterns is presented using hierarchical polymeric stamps with perfluoropolyether (PFPE). A dual-scale PFPE structure is made via two-step moulding process under partial photocrosslinking conditions. The hierarchical PFPE stamp enables multiscale transfer printing (MTP) of metal pattern in one step within microwells as well as on curved surfaces.

The mechanism of particle formation from submicrometer emulsion droplets by solvent evaporation is revisited. A combination of dynamic light scattering, fluorescence resonance energy transfer, zeta potential measurements, and fluorescence cross-correlation spectroscopy is used to analyze the colloids during the evaporation process. It is shown that a combination of different methods yields reliable and quantitative data for describing the fate of the droplets during the process. The results indicate that coalescence plays a minor role during the process; the relatively large size distribution of the obtained polymer colloids can be explained by the droplet distribution after their formation.

The preparation of nanoparticles by solvent evaporation from miniemulsion droplets is examined by various analytical methods. It is shown that coalescence plays a minor role in the polydispersity of the obtained nanoparticles.

High performance is reported for a symmetric ultracapacitor (UC) cell made up of hierarchically perforated graphene nanosheets (HPGN) as an electrode material with excellent values of energy density (68.43 Wh kg⁻¹) and power density (36.31 kW kg⁻¹). Perforations are incorporated in the graphite oxide (GO) and graphene system at room temperature by using silica nanoparticles as template. The symmetric HPGN-based UC cell exhibits excellent specific capacitance (Cs) of 492 F g⁻¹ at 0.1 A g⁻¹ and 200 F g⁻¹ at 20 A g⁻¹ in 1M H₂SO₄ electrolyte. This performance is further highlighted by galvanostatic charge–discharge study at 2 A g⁻¹ over a large number (1000) of cycles exhibiting 93% retention of the initial Cs. These property features are far superior as compared to those of symmetric UC cells made up of only graphene nanosheets (GNs), i.e. graphene sheets without perforations. The latter exhibit Cs of only 158 F g⁻¹ at 0.1 A g⁻¹ and the cells is not stable at high current density.

A high specific capacitance (Cs) value is obtained for a symmetric ultracapacitor (UC) cell in 1 M H₂SO₄ electrolyte by using hierarchically nanoperforated graphene nanosheets (HPGN) as an electrode material. Nanoperforations are introduced in graphene by simple stirring in silica nanoparticle dispersion followed by HF treatment. The HPGN is shown to deliver a remarkably high energy density (68.43 Wh kg⁻¹) as compared to earlier reports for graphene-based materials.

Droplet-based microreactors are used for the continuous production of Pd nanocrystals. Specifically, commercially available polytetrafluoroethylene (PTFE) tube and silica capillaries are utilized to fabricate a fluidic device capable of generating water-in-oil droplets. In addition to the feasibility of using such droplets as microreactors for conducting a synthesis, the ability to control the composition and concentration of reagents by adjusting the flow rates is demonstrated; reagents are mixed by periodically pinching the PTFE tube, and nanocrystals are produced with uniform size distribution in a continuous fashion. The capability to tailor the size and shape of the resultant nanocrystals is further demonstrated by introducing the reducing agent and capping agent at different flow rates to control the nucleation and growth processes. The ability to transform a bulk synthesis into a droplet-based system holds great potential for the development of a new route to the high-volume production of nanocrystals.

A simple fluidic device is used to generate droplet-based microreactors for the synthesis of uniform palladium nanocrystals in a continuous fashion. The size and shape of the nanocrystals could be controlled by varying the flow rates of the reducing agent and capping agent, respectively.

Silver nanowire (AgNW) random meshes have attracted considerable attention as flexible and high-performance transparent electrodes. Notably, post-treatment of the AgNW random meshes, such as thermal annealing, is usually required to guarantee comparable optical transparency and electrical conductivity to commercial indium tin oxide (ITO). Here, the integral elements of preparing a high-performance, large-area AgNW random mesh network are discussed. High-performance nanostructured transparent electrodes can be obtained without any post-treatment, thereby relieving the restrictions related to the substrate. Solvent washing and a large-area spray-coating method effectively reduce the wire–wire contact resistances, thus reducing or eliminating the requirement for post-treatment.

Solvent washing and spraying of silver nanowires decrease the sheet resistance of silver nanowire networks dramatically. The newly suggested methods eliminate post treatments such as annealing and pressing, which have been considered essential processes to reduce the sheet resistance and obtain ITO-comparable transparent electrodes.

The design of compartmentalized carriers for advanced drug delivery systems or artificial cells and organelles is of interest for biomedical applications. Herein, a polymer carrier microreactor that contains two different classes of subcompartments, multilayered polymer capsules and liposomes, is presented. 50 nm-diameter liposomes and 300 nm-diameter polymer capsules are encapsulated into a larger polymer carrier capsule, demonstrating control over the spatial positioning of the subcompartments, which are either ‘membrane-associated’ or 'free-floating’ in the aqueous interior. Selective and spatially dependent degradation of the 300 nm-diameter subcompartments (without destroying the structural integrity of the enzyme-loaded liposomes) is also shown, by performing an encapsulated enzymatic reaction using the liposomal subcompartments. These findings cover several important aspects toward the development of engineered compartmentalized carrier vessels for the creation of artificial cell mimics or advanced therapeutic delivery systems.

The assembly of a polymer capsule microreactor containing subcompartments of different composition, polymeric capsules and liposomes, is reported. Control over the position of the subcompartments is demonstrated, the polymeric subunits are selectively degraded, and cargo functionality is preserved within the liposomal subunits, as demonstrated through enzymatic reactions.

TiO₂ nanorod (NR) and nanotube (NT) arrays grown on transparent conductive substrates are attractive electrode for solar cells. In this paper, TiO₂ NR arrays are hydrothermally grown on FTO substrate, and are in situ converted into NT arrays by hydrothermally etching. The TiO₂ NR arrays are reported as single crystalline, but the TiO₂ NR arrays are demonstrated to be polycrystalline with a bundle of 2–5 nm single crystalline nanocolumns grown along [001] throughout the whole NR from bottom to top. TiO₂ NRs can be converted to NTs by hydrothermal selective etching of the (001) core and remaining the inert sidewall of (110) face. A growth mechanism of the NR and NT arrays is proposed. Quantum dot-sensitized solar cells (QDSCs) are fabricated by coating CdSe QDs on to the TiO₂ arrays. After conversion from NRs to NTs, more QDs can be filled in the NTs and the energy conversion efficiency of the QDSCs almost double.

TiO₂ nanorod (NR) arrays are hydrothermally grown on FTO substrate, and can be converted to nanotubes (NTs) by selective hydrothermal etching of the (001) core and remaining the inert sidewall of (110) face. After conversion from NRs to NTs, the CdSe quantum dot-sensitized solar cells almost double in energy conversion efficiency.

A novel surface-enhanced Raman scattering (SERS) sensor is developed for real-time and highly repeatable detection of trace chemical and biological indicators. The sensor consists of a polydimethylsiloxane (PDMS) microchannel cap and a nanopillar forest-based open SERS-active substrate. The nanopillar forests are fabricated based on a new oxygen-plasma-stripping-of-photoresist technique. The enhancement factor (EF) of the SERS-active substrate reaches 6.06 × 10⁶, and the EF of the SERS sensor is about 4 times lower due to the influence of the PDMS cap. However, the sensor shows much higher measurement repeatability than the open substrate, and it reduces the sample preparation time from several hours to a few minutes, which makes the device more reliable and facile for trace chemical and biological analysis.

A novel microfluidic SERS sensor for real-time and highly repeatable detection is presented. The sensor employs noble metal-covered nanopillar forests as a SERS-active substrate. The nanopillar forests are produced by an oxygen-plasma-stripping-of-photoresist technique. The substrate is capped by a polydimethylsiloxane microchannel structure. Compared with open SERS-active substrates, the sensors have much higher measurement repeatability, and they reduce the sample preparation time from several hours to a few minutes.

Layered assemblies of photosystem I, PSI, and/or photosystem II, PSII, on ITO electrodes are constructed using a layer-by-layer deposition process, where poly N,N′-dibenzyl-4,4′-bipyridinium (poly-benzyl viologen, PBV²⁺) is used as an inter-protein “glue”. While the layered assembly of PSI generates an anodic photocurrent only in the presence of a sacrificial electron donor system, such as dichlorophenol indophenol (DCPIP)/ascorbate, the PSII-modified electrode leads, upon irradiation, to the formation of an anodic photocurrent (while evolving oxygen), in the absence of any sacrificial component. The photocurrent is generated by transferring the electrons from the PSII units to the PBV²⁺ redox polymer. The charge-separated species allow, then, the injection of the electrons to the electrode, with the concomitant evolution of O₂. A layered assembly, consisting of a PSI layer attached to a layer of PSII by the redox polymer PBV²⁺, leads to an anodic photocurrent that is 2-fold higher, as compared to the anodic photocurrent generated by a PSII-modified electrode. This observation is attributed to an enhanced charge separation in the two-photosystem assembly. By the further nano-engineering of the two photosystems on the electrode using two different redox polymers, vectorial electron transfer to the electrode is demonstrated, resulting in a ca. 6-fold enhancement in the photocurrent. The reversed bi-layer assembly, consisting of a PSII layer linked to a layer of PSI by the PBV²⁺ redox polymer, yields, upon irradiation, an inefficient cathodic current. This observation is attributed to a mixture of photoinduced electron transfer reactions of opposing effects on the photocurrent directions in the two-photosystem assembly.

Effective photocurrents are observed upon illumination of a nano-engineered layer-by-layer assembly of photosystem I (PSI) and photosystem II (PSII) in the presence of two redox polymers and in the absence of any sacrificial donor.

Herein, a novel method to synthesize soluble, sub-micrometer sized protein aggregates is demonstrated by mixing native and denatured proteins without using bacteria and contaminating proteins. Ovalbumin (OVA) is employed as a model protein. The average size of the formed aggregates can be controlled by adjusting the fraction of denatured protein in the sample and it is possible to make unimodal size distributions of protein aggregates. OVA aggregates with a size of ∼95 nm are found to be more immunogenic compared to native OVA in a murine splenocyte proliferation assay. These results suggest that the novel method of engineering size specific sub-micrometer sized aggregates may constitute a potential route to increasing the efficacy of protein vaccines. The protein aggregates may also be promising for use in other applications including the surface functionalization of biomaterials and as industrial catalysis materials.

Soluble protein aggregates with adjustable sub-micrometer sizes can be synthesized by mixing native and denatured proteins without using bacteria and contaminating proteins. Ovalbumin (OVA) aggregates of ∼95 nm, produced with the presented method, are more immunogenic compared to native OVA in a murine splenocyte proliferation assay. The method of engineering size-specific aggregates may constitute a route to increase the efficacy of protein vaccines.

Metal nanostructures are the main building blocks of metamaterials and plasmonics which show many extraordinary properties not existing in nature. A simple and widely applicable method that can directly pattern metals with silicon molds without the need of resists, using pressures of <4 MPa and temperatures of 25–150 °C is reported. Three-dimensional structures with smooth and vertical sidewalls, down to sub-10 nm resolution, are generated in silver and gold films in a single patterning step. Using this nanopatterning scheme, large-scale vivid images through extraordinary optical transmission and strong surface-enhanced Raman scattering substrates are realized. Resistless nanoimprinting in metal (RNIM) is a new class of metal patterning that allows plasmonic nanostructures to be fabricated quickly, repeatedly, and at a low-cost.

Direct imprinting of metal films by silicon molds without the need of resists or any intermediate layers is demonstrated using pressures of <4 MPa and temperatures of 25–150 °C. Three-dimensional metal structures with smooth and vertical sidewalls, down to sub-10 nm resolution, are generated in silver and gold films. Large-scale vivid images through extraordinary optical transmission and strong surface-enhanced Raman scattering substrates are realized quickly, repeatedly, and at a low-cost.

An optofluidic platform for real-time monitoring of live cell secretory activities is constructed via Fano resonance in a gold nanoslit array. Large-area and highly sensitive gold nanoslits with a period of 500 nm are fabricated on polycarbonate films using the thermal-annealed template-stripping method. The coupling between gap plasmon resonance in the slits and surface plasmon polariton Bloch waves forms a sharp Fano resonance with intensity sensitivity greater than 11 000% per refractive index unit. The nanoslit array is integrated with a cell-trapping microfluidic device to monitor dynamic secretion of matrix metalloproteinase 9 (MMP-9) from human acute monocytic leukemia cells in situ. Upon continuous lipopolysaccharide (LPS) stimulation, MMP-9 secretion is detected within 2 h due to ultrahigh surface sensitivity and close proximity of the sensor to the target cells. In addition to the advantage of detecting early cell responses, the sensor also allows interrogation of cell secretion dynamics. Furthermore, the average secretion per cell measured using our system well matches previous reports while it requires orders of magnitude less cells. The optofluidic platform may find applications in fundamental studies of cell functions and diagnostics based on secretion signals.

Dynamic cell function is monitored by a nanoslit-based SPR sensor. The nanoslit array allows highly sensitive and label free detection of biomolecules. When combined with a microfluidic cell culture chip, secretion of matrix metalloproteinase 9 (MMP-9) from human monocytic cells is detected in real time upon lipopolysaccharide (LPS) stimulation.

The present study introduces a novel nanocarrier system comprising lipidic emulsomes and S-layer (fusion) proteins as functionalizing tools coating the surface. Emulsomes composed of a solid tripalmitin core and a phospholipid shell are created reproducibly with an average diameter of approximately 300 nm using temperature-controlled extrusion steps. Both wildtype (wt) and recombinant (r) S-layer protein SbsB of Geobacillus stearothermophilus PV72/p2 are capable of forming coherent crystalline envelope structures with oblique (p1) lattice symmetry, as evidenced by transmission electron microscopy. Upon coating with wtSbsB, positive charge of emulsomes shifts to a highly negative zeta potential, whereas those coated with rSbsB become charge neutral. This observation is attributed to the presence of a negatively charged glycan, the secondary cell wall polymer (SCWP), which is associated only with wtSbsB. The present study shows for the first time the ability of recombinant and wildtype S-layer proteins to cover the entire surface of emulsomes with its characteristic crystalline lattice. Furthermore, in vitro cell culture studies reveal that S-layer coated emulsomes can be uptaken by human liver carcinoma cells (HepG2) without showing any significant cytotoxicity over a wide range of concentrations. The utilization of S-layer fusion proteins equipped in a nanopatterned fashion by identical or diverse functions may lead to further development of emulsomes in nanomedicine, especially for drug delivery and targeting.

The present study introduces a biomimetic approach that utilizes one of the most precise self–organizing systems in nature, i.e. crystalline bacterial surface (S-) layer proteins, to design a novel multi-functional nanocarrier based on emulsomes. Emulsomes, composed of a solid fat core and a phospholipid shell, offer a high loading capacity for lipophilic agents. Beyond illustrating the potentials of emulsomes as a nanocarrier, this study is the first one showing the ability of S-layer (fusion) proteins to modify the surface of emulsomes resembling a virus envelope.

A highly efficient microfluidic 3D electrically small antenna is created using a simple fabrication technique. It is easy to construct simply by pneumatically inflating a planar microfluidic antenna into a spherical cap. It has premium performance around its hemispherical shape, combining a wide working band with high efficiency.

A new class of targeted and immune-evading nanocarrier made using only biological components and facile processes is assembled in a bottom-up fashion. Simple top-down sequential addition of immune-evading or receptor-specific antibody elements conjugated to biosurfactant protein DAMP4 promotes self-assembly at an interface previously formed in the presence of peptide surfactant AM1, leading to a functional display at the interface through non-covalent molecular self-assembly.

Nanosized drug carriers functionalized with moieties specifically targeting tumor cells are promising tools in cancer therapy, due to their ability to circulate in the bloodstream for longer periods and their selectivity for tumor cells, enabling the sparing of healthy tissues. Because of its biocompatibility, high bioresorbability, and responsiveness to pH changes, synthetic biomimetic nanocrystalline apatites are used as nanocarriers to produce multifunctional nanoparticles, by coupling them with the chemotherapeutic drug doxorubicin (DOXO) and the DO-24 monoclonal antibody (mAb) directed against the Met/Hepatocyte Growth Factor receptor (Met/HGFR), which is over-expressed on different types of carcinomas and thus represents a useful tumor target. The chemical-physical features of the nanoparticles are fully investigated and their interaction with cells expressing (GTL-16 gastric carcinoma line) or not expressing (NIH-3T3 fibroblasts) the Met/HGFR is analyzed. Functionalized nanoparticles specifically bind to and are internalized in cells expressing the receptor (GTL-16) but not in the ones that do not express it (NIH-3T3). Moreover they discharge DOXO in the targeted GTL-16 cells that reach the nucleus and display cytotoxicity as assessed in an MTT assay. Two different types of ternary nanoparticles are prepared, differing for the sequence of the functionalization steps (adsorption of DOXO first and then mAb or vice versa), and it is found that the ones in which mAb is adsorbed first are more efficient under all the examined aspects (binding, internalization, cytotoxicity), possibly because of a better mAb orientation on the nanoparticle surface. These multifunctional nanoparticles could thus be useful instruments for targeted local or systemic drug delivery, allowing a reduction in the therapeutic dose of the drug and thus adverse side effects. Moreover, this work opens new perspectives in the use of nanocrystalline apatites as a new platform for theranostic applications in nanomedicine.

Apatite nanoparticles functionalized with the chemotherapeutic doxorubicin and a monoclonal antibody targeting tumor cells overexpressing the tumor associated marker Met/Hepatocyte Growth Factor receptor specifically bind to and are internalized in cells expressing the receptor, and discharge doxorubicin, which reaches the nucleus and exert cytotoxicity. This work opens new perspectives in the use of nanocrystalline apatites as new platform for theranostic applications in nanomedicine.

A novel method is introduced for ultrahigh throughput and ultralow cost patterning of biomolecules with nanometer resolution and novel 2D digital nanodot gradients (DNGs) with mathematically defined slopes are created. The technique is based on lift-off nanocontact printing while using high-resolution photopolymer stamps that are rapidly produced at a low cost through double replication from Si originals. Printed patterns with 100 nm features are shown. DNGs with varying spacing between the dots and a record dynamic range of 4400 are produced; 64 unique DNGs, each with hundreds of thousands of dots, are inked and printed in 5.5 min. The adhesive response and haptotaxis of C2C12 myoblast cells on DNGs demonstrated their biofunctionality. The great flexibility in pattern design, the massive parallel ability, the ultra low cost, and the extreme ease of polymer lift-off nanocontact printing will facilitate its use for various biological and medical applications.

An easy, low cost, and massively parallel nanopatterning method based on lift-off nanocontact printing using disposable polymer masters is demonstrated. Its potential is shown by simultaneously patterning 64 digital nanodot gradients (DNGs) of proteins on a glass slide with a dynamic range of up to 4400 and comprising up to 419,790 200-nm-dots. Haptotaxis studies of C2C12 cells on DNGs of proteins and peptides validate DNGs for use in biological studies.

Natural protein (silk fibroin) nanoshells are assembled on the surface of Saccharomyces cerevisiae yeast cells without compromising their viability. The nanoshells facilitate initial protection of the cells and allow them to function in encapsulated state for some time period, afterwards being completely biodegraded and consumed by the cells. In contrast to a traditional methanol treatment, the gentle ionic treatment suggested here stabilizes the shell silk fibroin structure but does not compromise the viability of the cells, as indicated by the fast response of the encapsulated cells, with an immediate activation by the inducer molecules. Extremely high viability rates (up to 97%) and preserved activity of encapsulated cells are facilitated by cytocompatibility of the natural proteins and the formation of highly porous shells in contrast to traditional polyelectrolyte-based materials. Moreover, in a high contrast to traditional synthetic shells, the silk proteins are biodegradable and can be consumed by cells at a later stage of growth, thus releasing the cells from their temporary protective capsules. These on-demand encapsulated cells can be considered a valuable platform for biocompatible and biodegradable cell encapsulation, controlled cell protection in a synthetic environment, transfer to a device environment, and cell implantation followed by biodegradation and consumption of protective protein shells.

Biodegradable silk protein nanoshells are assembled on the surfaces of S. cerevisiae yeast cells. Initially acting as the protective coatings, it is suggested that silk shells are gradually digested by the cells without compromising their GFP-labeled activity.

Understanding the interfacial stress transfer between carbon nanotubes (CNTs) and polymer matrices is of great importance to the development of CNT-reinforced polymer nanocomposites. In this paper, an experimental study is presented of the interfacial strength between individual double-walled CNTs and poly(methyl methacrylate) (PMMA) using an in situ nanomechanical single-tube pull-out testing scheme inside a high-resolution electron microscope. By pulling out individual tubes with different embedded lengths, this work reveals the shear lag effect on the nanotube–polymer interface and demonstrates that the effective interfacial load transfer occurs only within a certain embedded length. These results show that the CNT–PMMA interface possesses an interfacial fracture energy within 0.054–0.80 J/m² and a maximum interfacial strength within 85–372 MPa. This work is useful to better understand the local stress transfer on nanotube–polymer interfaces.

The interfacial strength between individual double-walled carbon nanotubes and poly(methyl methacrylate) is characterized using an in situ nanomechanical single-tube pull-out testing scheme inside a high-resolution electron microscope. These measurements reveal the shear lag effect on the nanotube–polymer interface and demonstrate that the effective interfacial load transfer occurs only within a certain embedded length.

Micrometer-sized electrochemical capacitors have recently attracted attention due to their possible applications in micro-electronic devices. Here, a new approach to large-scale fabrication of high-capacitance, two-dimensional MoS₂ film-based micro-supercapacitors is demonstrated via simple and low-cost spray painting of MoS₂ nanosheets on Si/SiO₂ chip and subsequent laser patterning. The obtained micro-supercapacitors are well defined by ten interdigitated electrodes (five electrodes per polarity) with 4.5 mm length, 820 μm wide for each electrode, 200 μm spacing between two electrodes and the thickness of electrode is ∼0.45 μm. The optimum MoS₂-based micro-supercapacitor exhibits excellent electrochemical performance for energy storage with aqueous electrolytes, with a high area capacitance of 8 mF cm⁻² (volumetric capacitance of 178 F cm⁻³) and excellent cyclic performance, superior to reported graphene-based micro-supercapacitors. This strategy could provide a good opportunity to develop various micro-/nanosized energy storage devices to satisfy the requirements of portable, flexible, and transparent micro-electronic devices.

A new approach for large-scale fabrication of 2D MoS₂ film-based micro-supercapacitors is developed via a simple spray painting of MoS₂ nanosheets and subsequent laser patterning of the deposited film. The optimized MoS₂-based micro-supercapacitor exhibits excellent electrochemical performance for energy storage, with a high area capacitance of 8 mF cm⁻² and excellent cyclic performance, superior to state of the art carbon-based micro-supercapacitors.

Detection of the anthrax toxin, the protective antigen (PA), at the attomolar (aM) level is demonstrated by an electrical aptamer sensor based on a chemically derived graphene field-effect transistor (FET) platform. Higher affinity of the aptamer probes to PA in the aptamer-immobilized FET enables significant improvements in the limit of detection (LOD), dynamic range, and sensitivity compared to the antibody-immobilized FET. Transduction signal enhancement in the aptamer FET due to an increase in captured PA molecules results in a larger 30 mV/decade shift in the charge neutrality point (V_g,min) as a sensitivity parameter, with the dynamic range of the PA concentration between 12 aM (LOD) and 120 fM. An additional signal enhancement is obtained by the secondary aptamer-conjugated gold nanoparticles (AuNPs-aptamer), which have a sandwich structure of aptamer/PA/aptamer-AuNPs, induce an increase in charge-doping in the graphene channel, resulting in a reduction of the LOD to 1.2 aM with a three-fold increase in the V_g,min shift.

A chemically derived graphene field-effect transistor (FET) with aptamer recognition molecules shows ultra-sensitivity (12 aM∼120 fM) for anthrax toxin due to the higher affinity of the aptamer probe compared to that of an Ab probe. Detection capability with a limit of detection (LOD) at the attomolar level (1.2 aM) is achieved due to the amplification of signal transduction by the additional use of the secondary aptamer-conjugated gold nanoparticles (aptamer-AuNPs).

A wafer-scale patterning method for solution-processed graphene electrodes, named the transfer-and-reverse stamping method, is universally applicable for fabricating source/drain electrodes of n- and p-type organic field-effect transistors with excellent performance. The patterning method begins with transferring a highly uniform reduced graphene oxide thin film, which is pre-prepared on a glass substrate, onto hydrophobic silanized (rigid/flexible) substrates. Patterns of the as-prepared reduced graphene oxide films are then formed by modulating the surface energy of the films and selectively delaminating the films using an oxygen-plasma-treated elastomeric stamp with patterns. Reduced graphene oxide patterns with various sizes and shapes can be readily formed onto an entire wafer. Also, they can serve as the source/drain electrodes for benchmark n- and p-type organic field-effect transistors with enhanced performance, compared to those using conventional metal electrodes. These results demonstrate the general utility of this technique. Furthermore, this simple, inexpensive, and scalable electrode-patterning-technique leads to assembling organic complementary circuits onto a flexible substrate successfully.

Reproducible and effective wafer-scale patterning of reduced graphene oxide (rGO) electrodes by transfer-and-reverse stamping method is reported. The highly defined rGO micropatterns with various shapes are readily formed on rigid or flexible hydrophobized substrates and serve as the electrodes for high-performance n- and p-type OFETs and complementary inverters.

Highly luminescent semiconducting AgInS₂–ZnS solid solution nanorods are successfully prepared by a facile one-pot solvothermal method. The resulting solid solution nanorods with length of 32 ± 5 nm are formed by fast growth of the AgInS₂-rich solid solution head, followed by slow growth of the ZnS-rich solid solution tail. Photoluminescence studies on the solid solution nanorods reveal strong photoluminescence with peak emission wavelengths tunable from 650 to 700 nm.

A new form of nanotubular crystal structure is directly grown by a vapor-phase hydrothermal method via an epitaxial orientated crystal growth mechanism. The as-prepared nanotubes possess a unique multi-tunnel core-shell layered nanotubular structure with droplet shaped polygonal periphery and segmental crystal configuration. They are dimension-tunable and demonstrate superior ion exchange properties in terms of exchange rate and ion accommodating capacity.

Uniform Pt−Cu alloy nanocrystals in the shape of dendrite,, yolk-cage, and box structures are prepared via a facile wet-chemical reduction route in which glycine is demonstrated to alter the reduction kinetics of metal cations, critical to the morphology of the obtained product. These alloy nanocrystals exhibit superior specific activity and stability in the electro-oxidation of methanol.

The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically by using first-principles calculations. The results indicate that CoPc exhibits the highest catalytic activity for CO oxidation at room temperature with low energy barriers. By exploring the two well-established mechanisms for CO oxidation with O₂, namely, the Langmuir–Hinshelwood (LH) and the Eley–Rideal (ER) mechanisms, it is found that the first step of CO oxidation catalyzed by CoPc is the LH mechanism (CO + O₂ → CO₂ + O) with energy barrier as low as 0.65 eV. The second step proceeds via both ER and LH mechanisms (CO + O → CO₂) with small energy barriers of 0.10 and 0.12 eV, respectively. The electronic resonance among Co-3d, CO-2π*, and O₂-2π* orbitals is responsible for the high activity of CoPc. These results have significant implications for a novel avenue to fabricate organometallic sheet nanocatalysts for CO oxidation with low cost and high activity.

The catalytic behavior of transition metals (Sc to Zn) combined in polymeric phthalocyanine (Pc) is investigated systematically using first-principles calculations. CoPc exhibits the highest catalytic activity for CO oxidation at room temperature and its underlying catalytic mechanism is explored. The results have implications for the fabrication of organometallic sheet nanocatalysts with low cost and high activity.

A simple and low-cost solution synthesis is reported for low-crystalline 1.4 nm tobermorite-like calcium silicate hydrate (CSH) ultrathin nanosheets with a thickness of ∼2.8 nm and with a large specific surface area (SSA), via a reaction-rate-controlled precipitation process. The BET SSA of the CSH ultrathin nanosheets can reach as high as 505 m² g⁻¹. The CSH ultrathin nanosheets have little cytotoxicity and can be converted to anhydrous calcium silicate (ACS) ultrathin nanosheets with a well preserved morphology via a heat treatment process. The crystallinity of CSH ultrathin nanosheets can be improved by solvothermal treatment in water/ethanol binary solvents or a single solvent of water, producing well-crystalline 1.1 nm tobermorite-like CSH nanobelts or nanosheets. CSH ultrathin nanosheets acting as building blocks can self-assemble into layered nanostructures via three different routes. The CSH ultrathin nanosheets are investigated as promising adsorbents for protein (hemoglobin, Hb), drug (ibuprofen, IBU), and metal ions (Cr³⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺). The highest adsorbed percentages of Hb and IBU are found to be 83% and 94%, respectively. The highest adsorption capacities of Hb and IBU are found to be as high as 878 milligram Hb per gram CSH and 2.2 gram IBU per gram CSH, respectively. The ppm level metal ions can be totally adsorbed from aqueous solution in just a few minutes. Thus, the CSH ultrathin nanosheets are a promising candidate as excellent adsorbents in the biomedical field and for waste water treatment. Several empirical laws are summarized based on the adsorption profiles of Hb and IBU using CSH ultrathin nanosheets as the adsorbent. Furthermore, the ACS ultrathin nanosheets as adsorbents for Hb protein and IBU drug are investigated.

A simple and low-cost reaction-rate-controlled solution synthesis of calcium silicate hydrate (CSH) ultrathin nanosheets with a thickness of ∼2.8 nm and with a large specific surface area is reported. The CSH ultrathin nanosheets are excellent adsorbents for protein, drug, and metal ions and, thus, are promising for applications in biomedical fields and waste water treatment.

Millions of years of evolution have adapted spider webs to achieve a range of properties, including the well-known capture of prey, with efficient use of materials. One feature that remains poorly understood is the attachment disc, a network of silk fibers that mechanically anchors a web to its environment. Experimental observations suggest that one possible attachment disc adheres to a substrate through multiple symmetrically branched structures composed of sub-micrometer scale silk fibers. Here, a theoretical model is used to explore the adaptation of the strength of attachment of such an anchorage, and complementary mesoscale simulations are applied to demonstrate a novel mechanism of synergetic material and structural optimization, such that the maximum anchorage strength can be achieved regardless of the initial anchor placement or material type. The optimal delamination (peeling) angle is facilitated by the inherent extensibility of silk, and is attained automatically during the process of delamination. This concept of self-optimizing peeling angle suggests that attachment discs do not require precise placement by the spider, irrespective of adhesion strength. Additional hierarchical branching of the anchorage increases efficiency, where both the delamination force and toughness modulus increase with a splitting of the cross-sectional area.

How does a spider attach a web to the environment, in spite of unknown conditions? The answer is the unique attachment disc, a clustered network of piriform silk fibers that mechanically anchors a web. Through integrated theoretical, computational, and experimental analysis, the clever mechanism by which this structure provides a self-optimizing strong and robust attachment is elucidated.

A facile one-pot synthesis of Ag@Fe₂O₃ core–shell and Ag–Fe₂O₃ heteromer nanoparticles is developed, and the core–shell nanoparticles have shown superior antibacterial properties compared to their heteromer counterparts and plain Ag nanoparticles. The mechanism for the increased efficiency is proposed to be due to the enhanced Ag ion release from the iron oxide shell-protected pristine Ag surface.

Soluble covalent organic nanoframeworks up to generation 2.5 (G2.5) are synthesized with self-similar H-shaped conformations by using a bottom-up approach including iterative C–H bond functionalization. The electrical characteristics of nanoscale thin-film semiconductors of the conjugation-interrupted frameworks can be tuned by post-modification with diazonium salt.

Tandem assays of protein and glucose in combination with mannose-functionalized Fe₃O₄@SiO₂ and Ag@SiO₂ tag particles have promising potential in effective magnetic separation and highly sensitive and selective SERS assays of biomaterials. It is for the first time that tandem assay of glucose is developed using SERS based on the Con A-sandwiched microstructures between the functionalized magnetic and tag particles.

An optimized electrodropping system produces homogeneous core–shell microcapsules (C-S MCs) by using poly(L-lactic-co-glycolic acid) (PLGA) and alginate. Fluorescence imaging clearly shows the C-S domain in the MC. For release control, the use of high-molecular-weight PLGA (HMW 270 000) restrains the initial burst release of protein compared to that of low-MW PLGA (LMW 40 000). Layer-by-layer (LBL) assembly of chitosan and alginate on MCs is also useful in controlling the release profile of biomolecules. LBL (7-layer) treatment is effective in suppressing the initial burst release of protein compared to no LBL (0-layer). The difference of cumulative albumin release between HMW (7-layer LBL) and LMW (0-layer LBL) PLGA is determined to be more than 40% on day 5. When dual angiogenic growth factors (GFs), such as platelet-derived GF (PDGF) and vascular endothelial GF (VEGF), are encapsulated separately in the core and shell domains, respectively, the VEGF release rate is much greater than that of PDGF, and the difference of the cumulative release percentage between the two GFs is about 30% on day 7 with LMW core PLGA and more than 45% with HMW core PLGA. As for the angiogenic potential of MC GFs with human umbilical vein endothelial cells (HUVECs), the fluorescence signal of CD31+ suggests that the angiogenic sprout of ECs is more active in MC-mediated GF delivery than conventional GF delivery, and this difference is significant, based on the number of capillary branches in the unit area. This study demonstrates that the fabrication of biocompatible C-S MCs is possible, and that the release control of biomolecules is adjustable. Furthermore, MC-mediated GFs remain in an active form and can upregulate the angiogenic activity of ECs.

Core–shell microcapsules are fabricated from immiscible, biocompatible poly(L-lactic-co-glycolic acid) (PLGA) and alginate by using an electrodropping system. They hold the angiogenic growth factors (GFs) vascular endothelial GF (VEGF) in the shell alginate and platelet-derived GF (PDGF) in the core PLGA. The release profile of biomolecules is tunable by employing layer-by-layer assembly or by changing the polymer molecular weight.

Nano-objects are generated through 3D confined supramolecular assembly, followed by a sequential disintegration by rupturing the hydrogen bonding. The shape of the nano-objects is tunable, ranging from nano-disc, nano-cup, to nano-toroid. The nano-objects are pH-responsive. Functional materials for example inorganic or metal nanoparticles are easily complexed onto the external surface, to extend both composition and microstructure of the nano-objects.

Ordered mesoporous β-MgMoO₄ thin film electrodes with uniform pores averaging 19 nm in diameter are prepared through polymer templating of inorganic salt precursors. The unique combination of open mesopore cavities with nanocrystalline walls provides a beneficial microstructure for lithium-ion battery applications.

3D functional polymer brushes are fabricated by liquid-mediated scanning probe nanosculpting (LSPN). Surface-tethered functional polymer brushes, which are immersed in their good solvent, are mechanically cleaved away from the substrate by the AFM tip at high forces, and immediately imaged in situ with the same AFM tip at low applied forces.

Multiplexing, i.e., the application and integration of more than one ink in an interdigitated microscale pattern, is still a challenge for microcontact printing (μCP) and similar techniques. On the other hand there is a strong demand for interdigitated patterns of more than one protein on subcellular to cellular length scales in the lower micrometer range in biological experiments. Here, a new integrative approach is presented for the fabrication of bioactive microarrays and complex multi-ink patterns by polymer pen lithography (PPL). By taking advantage of the strength of microcontact printing (μCP) combined with the spatial control and capability of precise repetition of PPL in an innovative way, a new inking and writing strategy is introduced for PPL that enables true multiplexing within each repetitive subpattern. Furthermore, a specific ink/substrate platform is demonstrated that can be used to immobilize functional proteins and other bioactive compounds over a biotin–streptavidin approach. This patterning strategy aims specifically at application by cell biologists and biochemists addressing a wide range of relevant pattern sizes, easy pattern generation and adjustment, the use of only biofriendly, nontoxic chemicals, and mild processing conditions during the patterning steps. The retained bioactivity of the fabricated cm² area filling multiprotein patterns is demonstrated by showing the interaction of fibroblasts and neurons with multiplexed structures of fibronectin and laminin or laminin and ephrin, respectively.

Truly multiplexed micropatterns of bioactive inks are produced by polymer pen lithography (PPL). A new inking and writing strategy is presented that, taking advantage of the strength of microcontact printing (μCP) combined with the spatial control and capability of precise repetition and positioning of PPL, enables multicolored printing within each repetitive subpattern.

Fluorescence quenching microscopy (FQM) is demonstrated as a low-cost and high-throughput technique for seeing graphene-like 2D sheets such as MoS₂. FQM provides high contrast and layer resolution comparable to those of scanning electron microscopy, but allows the imaging of samples deposited on arbitrary substrates, including non-conductive substrates such as quartz. Solution fluorescence quenching studies suggest that FQM should be feasible for many other 2D materials such as WS₂, Bi₂Te₃, MoSe₂, NbSe₂, and TaS₂.

An NIR-responsive mesoporous silica coated upconverting nanoparticle (UCNP) conjugate is developed for controllable drug delivery and fluorescence imaging in living cells. In this work, antitumor drug doxorubicin (Dox) molecules are encapsulated within cross-linked photocaged mesoporous silica coated UCNPs. Upon 980 nm light irradiation, Dox could be selectively released through the photocleavage of theo-nitrobenzyl (NB) caged linker by the converted UV emission from UCNPs. This NIR light-responsive nanoparticle conjugate demonstrates high efficiency for the controlled release of the drug in cancer cells. Upon functionalization of the nanocarrier with folic acid (FA), this photocaged FA-conjugated silica-UCNP nanocarrier will also allow targeted intracellular drug delivery and selective fluorescence imaging towards the cell lines with high level expression of folate receptor (FR).

A NIR-controllable drug nanocarrier based on silica-coated upconverting nanoparticles is presented. Upon functionalization of the photoactive nanocarrier with folic acid, selective cell imaging and targeted drug delivery can be easily achieved in tumor cells with overexpression of folate receptor.

Near-infrared emitting, magnetic particles for combined optical and MR detection based on liposomes or artificial lipoproteins are presented. They provide a novel strategy for the luminescence sensitization of lanthanide cations (Yb³⁺, Nd³⁺) without covalent bonds between the chromophore and the lanthanide, and provide an unambiguous tool for monitoring the integrity of the liponanoparticles, via emission in the NIR region.

This paper advances the design of stimuli-responsive materials based on colloidal particles dispersed in liquid crystals (LCs). Specifically, thin films of colloid-in-liquid crystal (CLC) gels undergo easily visualized ordering transitions in response to reversible and irreversible (enzymatic) biomolecular interactions occurring at the aqueous interfaces of the gels. In particular, LC ordering transitions can propagate across the entire thickness of the gels. However, confinement of the LC to small domains with lateral sizes of ∼10 μm does change the nature of the anchoring transitions, as compared to films of pure LC, due to the effects of confinement on the elastic energy stored in the LC. The effects of confinement are also observed to cause the response of individual domains of the LC within the CLC gel to vary significantly from one to another, indicating that manipulation of LC domain size and shape can provide the basis of a general and facile method to tune the response of these LC-based physical gels to interfacial phenomena. Overall, the results presented in this paper establish that CLC gels offer a promising approach to the preparation of self-supporting, LC-based stimuli-responsive materials.

Formation of colloid-in-liquid crystal gels that are stable upon exposure to aqueous solutions of amphiphiles is reported. The gels can be driven through ordering transitions via interfacial interactions of synthetic and biological adsorbates. The gels also respond optically to enzymatic processes at their interfaces.

Inspired by Pearson's hard and soft acid-base (HSAB) principle, uniform amorphous Ni(OH)₂ nanoboxes with intact shell structures and various sizes are quickly fabricated by deliberately selecting S₂O₃²⁻ as the coordinating etchant toward Cu₂O templates and optimizing the reaction conditions. It is found that not only the solvent system but also the employing of a surfactant is vital for the fabrication of the nanoboxes. Ni(OH)₂ nanoboxes, as an example, demonstrate an improved electrochemical sensing ability for glucose, which might be due to their amorphous and hollow structural features.

Uniform amorphous Ni(OH)₂ nanoboxes with intact shell structures and various sizes are quickly fabricated by deliberately selecting S₂O₃²⁻ as the coordinating etchant toward Cu₂O templates and optimizing the reaction conditions. Ni(OH)₂ nanoboxes also demonstrate an enhanced electrochemical sensing ability for glucose, with excellent sensitivity, selectivity, and good long-term stability.

A class of core-shell nanoparticles possessing a layer of biocompatible shell and hydrophobic core with embedded oxygen-sensitive platinum-porphyrin (PtTFPP) dyes is developed via a radical-initiated microemulsion co-polymerization strategy. The influences of host matrices and the PtTFPP incorporation manner on the photophysical properties and the oxygen-sensing performance of the nanoparticles are investigated. Self-loading capability with cells and intracellular-oxygen-sensing ability of the as-prepared nanoparticle probes in the range 0%–20% oxygen concentration are confirmed. Polymeric nanoparticles with optimized formats are characterized by their relatively small diameter (<50 nm), core-shell structures with biocompatible shells, covalent-attachment-imparted leak-free construction, improved lifetime dynamic range (up to 44 μs), excellent storage stability and photostability, and facile cell uptake. The nanoparticles’ small sensor diameter and core-shell structure with biocompatible shell make them suitable for intracellular detection applications. For intracellular detection applications, the leak-free feature of the as-prepared nanoparticle sensor effectively minimizes potential chemical interferences and cytotoxicity. As a salient feature, improved lifetime dynamic range of the sensor is expected to enable precise oxygen detection and control in specific practical applications in stem-cell biology and medical research. Such a feature-packed nanoparticle oxygen sensor may find applications in precise oxygen-level mapping of living cells and tissue.

Core-shell-type oxygen nanosensors with optimized formats are developed. They are characterized by their relatively small diameter (<50 nm), biocompatible and protective shells, covalent-attachment-imparted leak-free construction, improved lifetime dynamic range (up to 44 μs), and excellent storage stability and photostability. Their facile cell uptake and ability to sense intracellular oxygen are confirmed.

Efficient charge transfer between ZnO quantum dots (QDs) and graphene is demonstrated by decorating ZnO QDs on top of graphene, with the assistance of oxygen molecules from the air. The electrical response of the device to UV light is greatly enhanced, and a photoconductive gain of up to 10⁷ can be obtained.

Monodisperse and uniform AuNP-decorated, dye-doped, superparamagnetic nanocomposites (Fe₃O₄@dye-hybrid@Au) are fabricated by using a simple method in which the Au NP formation and their attachment onto the core surface via S–Au covalent bonds proceeds almost simultaneously in a one-pot synthesis. The as-synthesized nanocomposites can simultaneously enhance the contrast effects for MR, CT, and cellular-sensitive optical imaging.

Electrical characteristics of individual cross-junction nanodevices consisting of two SnO₂ nanobelts are systematically investigated. The source–drain current along one nanobelt under constant source–drain voltage is not linearly varied with the ‘gate’ voltage applied on the terminal of the other one. The absolute increments for the source–drain and ‘gate’ current gradually increase as the gate voltage deviates from 0 V.

There are still challenges for the development of multifunctional carbon nanotubes (CNTs). Here, a multiwalled carbon nanotube (MWCNT)-based rolling circle amplification system (CRCAS) is reported which allows in situ rolling circle replication of DNA primer on the surface of MWCNTs to create a long single-strand DNA (ssDNA) where a large number of nanoparticles or proteins could be loaded, forming a nano-biohybridized 3D structure with a powerful signal amplification ability. In this strategy, the binding ability of proteins, hybridization, replication ability of DNA, and the catalytical ability of enzymes are integrated on a single carbon nanotube. The CRCAS is then used to develop colorimetric and chemiluminescent assays for the highly sensitive and specific detection of cancer protein markers, alpha-fetoprotein (AFP) and prostate specific antigen (PSA). The colorimetric CRCAS assay is 4000 times more sensitive than a conventional enzyme-linked immunosorbent assay (ELISA), and its concentration range is 10 000 times wider. Control experiments show that as low as 10 pg mL⁻¹ AFP or PSA could be detected even in the presence of interfering protein markers with a more than 10⁵-fold greater concentration in the sample, demonstrating the high specificity of the CRCAS assay. The limit of detection of the chemiluminescent CRCAS assays for AFP and PSA are 5 fg mL⁻¹ (70 aM) and 10 fg mL⁻¹ (0.29 fM), respectively, indicating that the sensitivity is much higher than that of the colorimetric CRCAS assay. Importantly, CRCAS works well with real biological samples.

Combining carbon nanotubes (CNTs) using DNA rolling circle amplification, the binding ability of proteins, hybridization, the replication ability of DNA, and the catalytical ability of enzymes are all integrated onto a single carbon nanotube. In this system, a large number of signal labels are then allowed to bind to an individual carbon nanotube, resulting in amplified signals. The signaling system shows superior performance in the detection of cancer markers in biological fluids.

An efficient evaporation-induced coating method combining microwave-assisted hydrothermal transformation and annealing is developed to fabricate an ideal electrode material from composites with a layer of hydrous RuO₂ on mesoporous silica nanoparticles (MSNs), for a high-performance supercapacitor. Total and RuO₂-based specific capacitances are as high as 1125 and 2000 F g⁻¹, respectively.

External electric fields readily align birefringent block-copolymer mesophases. In this study the effect of gold nanoparticles on the electric-field-induced alignment of a lamellae-forming polystyrene-block-poly(2-vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric-field-assisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such films under benign experimental conditions.

Similar to neat block copolymers, nanocomposites composed of polystyrene-block-poly(2-vinyl pyridine) and gold nanoparticles can be aligned in electric fields, which leads to a striped and aligned structure of nanoparticles after removal of the polymer. The onset of domain alignment in the presence of nanosized gold particles occurs at a substantially lower field than for corresponding films in the absence of particles, and decreases with increasing nanoparticle concentration.

A new Schottky junction ultraviolet photodetector (UVPD) is fabricated by coating a free-standing ZnO nanorod (ZnONR) array with a layer of transparent monolayer graphene (MLG) film. The single-crystalline [0001]-oriented ZnONR array has a length of about 8–11 μm, and a diameter of 100∼600 nm. Finite element method (FEM) simulation results show that this novel nanostructure array/MLG heterojunction can trap UV photons effectively within the ZnONRs. By studying the I–V characteristics in the temperature range of 80–300 K, the barrier heights of the MLG film/ZnONR array Schottky barrier are estimated at different temperatures. Interestingly, the heterojunction diode with typical rectifying characteristics exhibits a high sensitivity to UV light illumination and a quick response of millisecond rise time/fall times with excellent reproducibility, whereas it is weakly sensitive to visible light irradiation. It is also observed that this UV photodetector (PD) is capable of monitoring a fast switching light with a frequency as high as 2250 Hz. The generality of the above results suggest that this MLG film/ZnONR array Schottky junction UVPD will have potential application in future optoelectronic devices.

A new Schottky junction ultraviolet photodetector is fabricated by coating a free-standing ZnO nanorod array with a monolayer graphene film. This special structure is able to trap UV light within ZnO nanorods, and exhibits high sensitivity to UV light irradiation with good reproducibility and fast response time.

An assembly strategy is reported such that segmented nanorods fabricated through template-assisted methods can be robustly transferred and tethered to a pre-functionalized substrate with excellent uniformity over large surface areas. After embedding the rods, sacrificial nickel segments were selectively etched leaving behind strongly coupled segmented gold nanorods with gaps between rods below 40 nm and as small as 2 nm. Hyper-spectral imaging is utilized to measure Rayleigh scattering spectra from individual and coupled nanorod elements in contrast to common bulk measurements. This approach discerns the effects of not only changing segment and gap size but also the presence of characteristic defects on the plasmonic coupling between closely spaced nanorods. Polarized hyper-spectral measurements are conducted to provide direct observation of the anisotropic plasmonic resonance modes in individual and coupled nanorods, which are close to those predicted by computer simulations for nanorods with ideal shapes. Some common deviations from ideal shape such as non-flat facets and asymmetric tails are demonstrated to result in the appearance of characteristic plasmon resonances, which have not been considered before. The large-scale assembly of coupled noble nanostructures with fine control over geometry and high uniformity provides means to strongly tune the scattering, absorption, and near-field plasmonic properties through the geometric arrangement of precisely controlled nanorod segments.

Segmented nanorods fabricated through template-assisted methods are tethered to a pre-functionalized substrate with excellent uniformity over large areas. After embedding the rods, sacrificial nickel segments are selectively etched, leaving strongly coupled segmented gold nanorods with gaps between rods of between 2 and 40 nm. Hyper-spectral imaging measures Rayleigh scattering spectra from individual and coupled nanorod elements, and polarized hyper-spectral measurements provide direct observation of the anisotropic plasmonic resonance modes in individual and coupled nanorods.

Many delivery methods have been developed to improve the therapeutic efficacy and facilitate the clinical translation of nucleic acid-based therapeutics. A facile surface-mediated nucleic acid delivery by lipoplexes is prepared in a microwell array, which combines the advantages of lipoplexes as an efficient carrier system, surface-mediated delivery, and the control of surface topography. Uniform disc-like lipoplexes containing nucleic acids are formed in the microwell array with a diameter of ∼818 nm and thickness of ∼195 nm. The microwell array-mediated delivery of lipoplexes containing FAM-oligodeoxynucleotides is ∼18.6 and ∼10.6 times more efficient than the conventional transfection method in an adherent cell line (A549 non-small cell lung cancer cells) and a suspension cell line (KG-1a acute myelogenous leukemia cells), respectively. MicroRNA-29b is then used as a model nucleic acid to investigate the therapeutic efficacy of lipoplexes delivered by the microwell array. Compared to conventional transfection methods, the effective therapeutic dosage of microRNA-29b is reduced from the microgram level to the nanogram level by lipoplexes prepared in the microwell array. The microwell array is also a very flexible platform. Both nucleic acid therapeutics and imaging reagents are incorporated in lipoplexes and successfully delivered to A549 cells, demonstrating its potential applications in theranostic medicine.

Uniform lipoplexes containing nucleic acids are prepared in a microwell array by discontinuous dewetting in a facile and well controlled manner. The microwell array-mediated delivery of lipoplexes containing nucleic acids is more efficient than a conventional transfection method, and thus significantly enhances the therapeutic efficacy at much lower effective doses of therapeutic reagents. Microwell arrays are also a very flexible platform that can be used to deliver multifunctional lipoplexes for applications in theranostic medicine.

A hydrogel biochip combining microfluidic mixing and orthogonal supplementation strategies is developed and validated to allow facile generation of libraries of optically transparent 3D culture microenvironments. Live, on-chip tracing of embryonic stem cell differentiation and endothelial cell tubulogenesis confirms that the platform can be used to both create communities of discrete 3D microenvironments as well as to locally monitor subsequent divergent responses at both single cell and multi-cell scales.

The role of surface chemistry on the toxicity of Ag nanoparticles is investigated using Saccharomyces cerevisiae yeast as a platform for evaluation. Combining the shape-controlled synthesis of Ag nanoparticles with a comprehensive characterization of their physicochemical properties, an understanding is formed of the correlation between the physicochemical parameters of nanoparticles and the inhibition growth of yeast cells upon the introduction of nanoparticles into the cell culture system. Capping agents, surface facets, and sample stability—the three experimental parameters that are inherent from the wet-chemical synthesis of Ag nanoparticles—have a strong impact on toxicity evaluation. Hence, it is important to characterize surface properties of Ag nanoparticles in the nature of biological media and to understand the role that surface chemistry may interplay to correlate the physicochemical properties of nanoparticles with their biological response upon exposure. This work demonstrates the great importance of surface chemistry in designing experiments for reliable toxicity evaluation and in mitigating the toxicity of Ag nanoparticles for their safe use in future commercialization.

The role of surface chemistry on the toxicity of Ag nanoparticles is investigated using Saccharomyces cerevisiae yeast as a platform for evaluation. It reveals that capping agents, surface facets, and sample stability—the three experimental parameters that are inherent from the wet-chemical synthesis of Ag nanoparticles—have a strong impact on toxicity evaluation.

In the past decades, numerous types of nanomedicines have been developed for the efficient and safe delivery of nucleic acid-based drugs for cancer therapy. Given that the destination sites for nucleic acid-based drugs are inside cancer cells, delivery systems need to be both targeted and shielded in order to overcome the extracellular and intracellular barriers. One of the major obstacles that has hindered the translation of nanotechnology-based gene-delivery systems into the clinic has been the complexity of the design and assembly processes, resulting in non-uniform nanocarriers with unpredictable surface properties and efficiencies. Consequently, no product has reached the clinic yet. In order to address this shortcoming, a multifunctional targeted biopolymer is genetically engineered in one step, eliminating the need for multiple chemical conjugations. Then, by systematic modulation of the ratios of the targeted recombinant vector to PEGylated peptides of different sizes, a library of targeted–shielded viral-mimetic nanoparticles (VMNs) with diverse surface properties are assembled. Through the use of physicochemical and biological assays, targeted–shielded VMNs with remarkably high transfection efficiencies (>95%) are screened. In addition, the batch-to-batch variability of the assembled targeted–shielded VMNs in terms of uniformity and efficiency is examined and, in both cases, the coefficient of variation is calculated to be below 20%, indicating a highly reproducible and uniform system. These results provide design parameters for engineering uniform, targeted–shielded VMNs with very high cell transfection rates that exhibit the important characteristics for in vivo translation. These design parameters and principles could be used to tailor-make and assemble targeted–shielded VMNs that could deliver any nucleic acid payload to any mammalian cell type.

Design parameters are described for the reproducible production of targeted and shielded nanoparticles that are highly efficient, safe, customizable and uniform, and meet the criteria for reproducibility. Therefore, they exhibit all the major necessary characteristics for in vivo translation.

In this study, zebrafish larvae are introduced as an in vivo platform to examine the neurotoxicity and developmental toxicity associated with continuous exposure to a concentration gradient of different sizes of SiO₂ nanoparticles (15 nm and 50 nm diameter) to determine the dose effect and size effect of SiO₂ nanoparticle (NP)-induced toxicity. Bovine serum albumin (BSA-V) is utilized as a stabilizing agent to prevent coagulation of the SiO₂ nanoparticles. To the best of our knowledge, this study is the first to describe locomotor activity assays linking rest/wake behavioral profiles for the purpose of investigating the neurotoxicity of NPs. In addition, developmental toxicological endpoints including mortality, LC₅₀, malformation, and cartilaginous deformity are assessed. The results show a concentration-dependent increase in behavioral neurotoxicity, mortality, and malformation among larvae treated with the SiO₂ nanoparticles of 15 nm and 50 nm. A comparison of the 15 nm and 50 nm NPs by K-means clustering analysis demonstrates that the 15 nm NPs have a greater neurotoxic effect than the 50 nm NPs, with the 50 nm NPs exhibiting greater developmental toxicity on the zebrafish larvae than the 15 nm NPs.

Locomotor activity assays linking rest/wake behavioral profiles are used to investigate the neurotoxicity of SiO₂ nanoparticles (NPs). In addition, developmental toxicological endpoints including mortality, LC₅₀, malformation, and cartilaginous deformity are assessed. The results indicate a concentration-dependent increase in behavioral neurotoxicity and developmental toxicity among larvae treated with the SiO₂ nanoparticles of 15 nm and 50 nm, with 15 nm NPs having a greater neurotoxic effect than 50 nm NPs. In terms of larval development, the 50 nm NPs are more toxic.

Lyophilic but not sticky! A lyophilic yet nonwettable surface seems self-contradictory, however, a nanostructured super-lyorepellent surface is used to reveal that a lyophilic nonwettable state is theoretically feasible in an oil/water/air/solid four-phase system. This finding may throw light on multiphase interface behavior.

Conjugated polymers (CPs) are promising materials for fluorescence imaging application. However, a significant problem in this field is the unexplained abnormally low fluorescence brightness (or number of fluorescence photons detected per one excitation photon) exhibited by most of CP single chains in solid polymer hosts. Here it is shown that this detrimental effect can be fully avoided for short chains of polyfluorene-bis-vinylphenylene (PFBV) embedded in a host polymer matrix of PMMA, if the conjugated backbone is insulated by cyclodextrin rings to form a polyrotaxane (PFBV-Rtx). Fluorescence kinetics and quantum yields are measured for the polymers in liquid solutions, pristine films, and solid PMMA blends. The fluorescence brightness of PFBV-Rtx single chains dispersed in a solid PMMA is very close to that expected for a chain with 100% fluorescence quantum yield, while the unprotected PFBV chains of the same length possess 4 times lower brightness. Despite this, the fluorescence decay kinetics are the same for both polymers, suggesting the presence of static or ultrafast fluorescence quenching in the unprotected polymer. About 80% of an unprotected PFBV chain is estimated to be completely quenched. The hypothesis is that the cyclodextrin rings prevent the quenching by working as ‘bumpers’ reducing the mechanical forces applied by the host polymer to the conjugated backbone and help retaining its conformational freedom. While providing a recipe for making CP fluorescence bright at the single-molecule level, these results identify a lack of fundamental understanding in the community of the influence of the environment on excited states in conjugated materials.

What makes some organic macromolecules and particles brighter fluorophores than others? How can one avoid the so called ‘dark matter’ formation in conjugated polymers which limits their fluorescence ability? This study at the single-molecule level gives an answer.

Fluorescent magnetic colloidal nanoparticles (FMCNPs) are produced by a two-step, seed emulsifier-free emulsion polymerization in the presence of oleic acid and sodium undecylenate-modified Fe₃O₄ nanoparticles (NPs). The Fe₃O₄/poly(St-co-GMA) nanoparticles are first synthesized as the seed and Eu(AA)₃Phen is copolymerized with the remaining St and GMA to form the fluorescent polymer shell in the second step. The uniform core–shell structured FMCNPs with a mean diameter of 120 nm exhibit superparamagnetism with saturation magnetization of 1.92 emu/g. Red luminescence from the FMCNPs is confirmed by the salient fluorescence emission peaks of europium ions at 594 and 619 nm as well as 2-photon confocal scanning laser microscopy. The in vitro cytotoxicity test conducted using the MTT assay shows good cytocompatibility and the T₂ relaxivity of the FMCNPs is 353.86 mM⁻¹S⁻¹ suggesting its potential in magnetic resonance imaging (MRI). In vivo MRI studies based on a rat model show significantly enhanced T₂-weighted images of the liver after administration and prussian blue staining of the liver tissue slice reveals accumulation of FMCNPs in the organ. The cytocompatibility, superparamagnetism, and excellent fluorescent properties of FMCNPs make them suitable for biological imaging probes in MRI and optical imaging.

Fluorescent magnetic colloidal nanoparticles (FMCNPs) containing Eu(AA)₃Phen are synthesized by seed emulsifier-free emulsion polymerization, with Eu³⁺ covalently bonded in the polymer chain. The FMCNPs with excellent luminescence and superparamagnetic properties could be used as multimodal magnetic resonance/optical imaging probes, as demonstrated by in vitro, in vivo MRI experiments and confocal scanning laser microscopy imaging.

Si–C hybrid nanofibers with a core-shell structure of Si nanoparticles confined in porous carbon nanofibers are fabricated by a single-nozzle electrospinning technique. The as-obtained Si nanoparticles/porous carbon hybrid nanofibers exhibit excellent properties in terms of cycling performance and rate capabilities for application as anode materials for lithium-ion batteries.

Giant, cell-sized polymersomes are functionalized and patterned at the single vesicle level. Microfluidic methods are employed to generate uniform diameter vesicles with high loading efficiencies and microcontact printing is used to generate patterns of adhesive ligand. A simple sensory capability is demonstrated with the immobilized array of vesicles.

Nanoparticles are increasingly used in medical applications such as drug delivery, imaging, and biodiagnostics, particularly for cancer. The design of nanoparticles for tumor delivery has been largely empirical, owing to a lack of quantitative data on angiogenic tissue sequestration. Using fluorescence correlation spectroscopy, the deposition rate constants of nanoparticles into angiogenic blood vessel tissue are determined. It is shown that deposition is dependent on surface charge. Moreover, the size dependency strongly suggests that nanoparticles are taken up by a passive mechanism that depends largely on geometry. These findings imply that it is possible to tune nanoparticle pharmacokinetics simply by adjusting nanoparticle size.

Nanoparticles circulating in angiogenic blood vessels will partition into surrounding tissues through fenestrations in the blood vessel walls. This partitioning depends on nanoparticle properties such as surface charge and size. The size dependence of partitioning rates found here suggests that the mechanism is largely controlled by geometry. Thus, the angiogenic blood vessels function like a size exclusion filter.

Carbon nanotubes (CNTs) hold promise in manufacturing, environmental, and biomedical applications, as well as food and agricultural industries. Previous observations have shown that CNTs have antimicrobial activity; however, the impact of CNTs to human gut microbes has not been investigated. Here, the antibacterial activity of CNTs against the microbes commonly encountered in the human digestion system—L. acidophilus, B. adolescentis, E. coli, E. faecalis, and S. aureus—are evaluated. The bacteria studied include pathogenic and non-pathogenic, gram-positive and negative, and both sphere and rod strains. In this study, CNTs, including single-walled CNTs (SWCNTs, 1–3 μm), short and long multi-walled CNTs (s-MWCNTs: 0.5–2 μm; l-MWCNTs: >50 μm), and functionalized multi-walled CNTs (hydroxyl- and carboxyl-modification, 0.5–2 μm), all have broad-spectrum antibacterial effects. Notably, CNTs may selectively lyse the walls and membranes of human gut microbes, depending on not only the length and surface functional groups of CNTs, but also the shapes of the bacteria. The mechanism of antibacterial activity is associated with their diameter-dependent piercing and length-dependent wrapping on the lysis of microbial walls and membranes, inducing release of intracellular components DNA and RNA and allowing a loss of bacterial membrane potential, demonstrating complete destruction of bacteria. Thin and rigid SWCNT show more effective wall/membrane piercing on spherical bacteria than MWCNTs. Long MWCNT may wrap around gut bacteria, increasing the area making contact with the bacterial wall. This work suggests that CNTs may be broad-spectrum and efficient antibacterial agents in the gut, and selective application of CNTs could reduce the potential hazard to probiotic bacteria.

Carbon nanotubes (CNT)s can selectively lyse the walls and membranes of human gut bacteria, depending on not only the length and surface functional groups of CNTs, but also the shapes of bacteria. The mechanism of antibacterial activity is associated with their diameter-dependent piercing and length-dependent wrapping. CNTs have potential as effective, selective, and broad-spectrum antibacterial agents, especially against drug-resistant bacteria.

NIR-emitting CdSeTe/CdS/ZnS core/shell/shell QD-encoded microbeads are combined with common flow cytometry with one laser for multiplexed detection of hepatitis B virus (HBV). A facile one-pot synthetic route is developed to prepare CdSeTe/CdS/ZnS core/shell/shell QDs with high photoluminescence quantum yield and excellent stability in liquid paraffin, and a Shirasu porous glass (SPG) membrane emulsification technique is applied to incorporate the QDs into polystyrene–maleic anhydride (PSMA) microbeads to obtain highly fluorescent QD-encoded microbeads. The relatively wide NIR photoluminescence full width half maximum of the CdSeTe/CdS/ZnS QDs is used to develop a ‘single wavelength’ encoding method to obtain different optical codes by changing the wavelengh and emission intensity of the QDs incorporated into the microbeads. Moreover, a detection platform combining NIR-emitting CdSeTe/CdS/ZnS QD-encoded microbeads and Beckman Coulter FC 500 flow cytometry with one laser of 488 nm is successfully used to conduct a 2-plex hybridization assay for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and a 3-plex hybridization assay for hepatitis B surface antibody (HBsAb), hepatitis B e antibody (HBeAb), and hepatitis B core antibody (HBcAb), which suggests the promising application of NIR QD-encoded microbeads for multiplex immunoassays.

A platform based on highly-fluorescent CdSeTe/CdS/ZnS NIR-emitting QD-encoded microbeads prepared by an SPG membrane emulsification technique are successfully combined with flow cytometry and a single 488 nm laser for multiplexed assays of biological samples.

A facile, robust approach to the synthesis of Au cubic nanoframes is described. The synthesis involves three major steps: 1) preparation of Au–Ag alloyed nanocages using a galvanic replacement reaction between Ag nanocubes and HAuCl₄; 2) deposition of thin layers of pure Au onto the surfaces of the nanocages by reducing HAuCl₄ with ascorbic acid, and; 3) formation of Au cubic nanoframes through a dealloying process with HAuCl₄. The key to the formation of Au cubic nanoframes is to coat the surfaces of the Au–Ag nanocages with sufficiently thick layers of Au before they are dealloyed. The Au layer could prevent the skeleton of a nanocage from being fragmented during the dealloying step. The as-prepared Au cubic nanoframes exhibit tunable localized surface plasmon resonance peaks in the near-infrared region, but with much lower Ag content as compared with the initial Au–Ag nanocages.

Cubic nanoframes of Au are synthesized by integrating galvanic replacement with deposition of Au and dealloying of Ag. The as-prepared cubic nanoframes exhibit tunable localized surface plasmon resonance peaks in the near-infrared region, but with much lower Ag content as compared with the conventioanl Au–Ag nanocages.

The influence of surface modifications on the mechanical properties of epoxy-hexagonal boron nitride nanoflake (BNNF) nanocomposites is investigated. Homogeneous distributions of boron nitride nanoflakes in a polymer matrix, preserving intrinsic material properties of boron nitride nanoflakes, is the key to successful composite applications. Here, a method is suggested to obtain noncovalently functionalized BNNFs with 1-pyrenebutyric acid (PBA) molecules and to synthesize epoxy–BNNF nanocomposites with enhanced mechanical properties. The incorporation of noncovalently functionalized BNNFs into epoxy resin yields an elastic modulus of 3.34 GPa, and 71.9 MPa ultimate tensile strength at 0.3 wt%. The toughening enhancement is as high as 107% compared to the value of neat epoxy. The creep strain and the creep compliance of the noncovalently functionalized BNNF nanocomposite is significantly less than the neat epoxy and the nonfunctionalized BNNF nanocomposite. Noncovalent functionalization of BNNFs is effective to increase mechanical properties by strong affinity between the fillers and the matrix.

The influence of surface modifications on the mechanical properties of epoxy-hexagonal boron nitride nanoflake (BNNF) nanocomposites is investigated. The BNNFs chemically surface modified by noncovalent functionalization are prohibited from stacking and aggregation, resulted in homogeneous dispersions in the epoxy matrix with strong interfacial interactions. The incorporation of noncovalently functionalized BNNFs into epoxy resin yields outstanding strength and toughness at low BNNF loadings.

A functional device to mimic the beetles of the genus Stenus is fabricated. A superhydrophobic hull is employed to replace the body of the beetles, with an attached reservoir to store low-surface-energy compounds to mimic the beetle's pygidial gland, and a pH-responsive mesh acts as its gland end, whose locomotion from static to mobile can respond to the pH value transformation.

Ultrathin triangular gold nanoframes are synthesized in high yield through selective gold deposition on the edges of triangular silver nanoprisms and subsequent silver etching with mild wet etchants. These ultrathin gold nanoframes are surfactant-free with tailorable ridge thickness from 1.8 to 6 nm and exhibit adjustable and distinct surface plasmon resonance bands in the visible and near-IR region. In comparison, etching of the nanoprism template by galvanic replacement can only create frame structures with much thicker ridges, which have much lower catalytic activity for 4-nitrophenol reduction than the ultrathin gold nanoframes.

Ultrathin triangular gold nanoframes with ridge thickness down to 1.8 nm have been synthesized in high yield by using a silver nanoprism as a sacrificial template. The ridges of the nanoframes are surfactant-free and enable a catalytic activity in 4-nitrophenol reduction superior to that of thin nanoframes made by galvanic replacement.

Photonic crystal materials are developed from colloidal crystal fibers or beads. As the fibers have cylindrical symmetry, the fiber-composed PhCs show anisotropic angle independence. By contrast, the bead-composed PhCs display angle-independent structural colors because of the spherical symmetry of their bead elements.

A one-pot two-phase method for the direct synthesis of small Au (Au₁₅ and Au₁₈) nanoclusters (NCs) of high purity is developed. A mild reductant is combined with two equilibria (i.e., equilibrium partition and aggregation–dissociation equilibrium) to provide a constant reaction environment for the formation of monodisperse small Au NCs. The pH sensitivity of the aggregation–dissociation equilibrium is used to tailor the cluster size.

Free-standing colloidal arrays can be easily transferred to supported fibers. These films conform and provide the template to have consistent submicrometer and nanometer features transferred to the periphery of rough, 7 μm diameter fibers. This technique is adjustable to a number of fiber surfaces and colloidal template sizes.

Microchannels are fabricated using a photosensitive polymer to which microporosity is tuned with different X-ray doses. Using hard X-ray irradiation, the micropattern is positioned with various geometries in a multi-level, three-dimensional structure, while controlling the pore size and transport properties of small molecules. This highly reliable fabrication process has potential for use in microfluidic devices with enhanced transport properties through microchannels.

Development of portable biosensors has broad applications in environmental monitoring, clinical diagnosis, public health, and homeland security. There is an unmet need for pathogen detection at the point-of-care (POC) using a fast, sensitive, inexpensive, and easy-to-use method that does not require complex infrastructure and well-trained technicians. For instance, detection of Human Immunodeficiency Virus (HIV-1) at acute infection stage has been challenging, since current antibody-based POC technologies are not effective due to low concentration of antibodies. In this study, we demonstrated for the first time a label-free electrical sensing method that can detect lysed viruses, i.e. viral nano-lysate, through impedance analysis, offering an alternative technology to the antibody-based methods such as dipsticks and Enzyme-linked Immunosorbent Assay (ELISA). The presented method is a broadly applicable platform technology that can potentially be adapted to detect multiple pathogens utilizing impedance spectroscopy for other infectious diseases including herpes, influenza, hepatitis, pox, malaria, and tuberculosis. The presented method offers a rapid and portable tool that can be used as a detection technology at the POC in resource-constrained settings, as well as hospital and primary care settings.

There is an unmet clinical need to detect HIV-1 at acute infection stage where current antibody based point-of-care (POC) technologies are not effective due to the low concentration of antibodies. To overcome this clinical diagnostic barrier, a simple, fast, and affordable diagnostic tool is developed that enables HIV-1 detection during the acute stage of the disease using the unique electrical signature of viral nano-lysates.

Electrospun fiber meshes are patterned at length scales comparable to or lower than their fiber diameter. Simple nano- and microgrooves and closed geometric shapes are imprinted in different tones using a fast imprint process at physiological temperatures. Human mesenchymal stromal cells cultured on patterned scaffolds show differences in cellular morphology and cytoskeleton organization. Microgrooved electrospun fibers support upregulation of alkaline phosphatase and bone morphogenetic protein-2 gene expression when cells are cultured in osteogenic medium.

The fabrication of a versatile nanocarrier based on agglomerated structures of gold nanoparticle (Au NP)–lysozyme (Lyz) in aqueous medium is reported. The carriers exhibit efficient loading capacities for both hydrophilic (doxorubicin) and hydrophobic (pyrene) molecules. The nanocarriers are finally coated with an albumin layer to render them stable and also facilitate their uptake by cancer cells. The interaction between agglomerated structures and the payloads is non-covalent. Cell viability assay in vitro showed that the nanocarriers by themselves are non-cytotoxic, whereas the doxorubicin-loaded ones are cytotoxic, with efficiencies higher than that of the free drug. Transmission electron microscopy and fluorescence microscopy along with flow cytometry analysis confirm the uptake of the drug-loaded nanocarriers by a human cervical cancer HeLa cell line. Field-emission scanning electron microscopy reveals the formation of apoptotic bodies leading to cell death, confirming the release of the payloads from the nanocarriers into the cell. Overall, the findings suggest the fabrication of novel Au NP–protein agglomerate-based nanocarriers with efficient drug-loading and -releasing capabilities, enabling them to act as multimodal drug-delivery vehicles.

Gold nanoparticle–lysozyme agglomerate represents a new nanocarrier, which hosts hydrophilic as well as hydrophobic molecules with a high capacity, and remains stable in the medium upon coating with albumin. Cancer cells—in vitro—internalize the doxorubicin-loaded nanocarriers, leading to their apoptotic cell death.

Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H₂O₂ is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H₂O₂ alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials.

Human eosinophil peroxidase (EPO) is able to degrade SWCNTs in vitro in the presence of H₂O₂. EPO is one of the major oxidant-generating enzymes present in human lung during inflammatory states. The biodegradation of SWCNTs is evidenced also in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. These results are relevant to potential respiratory exposure to carbon nanotubes.

The use of a nanosensor (AuC@Urease) based on an NIR-emitting gold cluster and urease enzyme selectively detects urea in whole blood. The detection is based on an enzyme-specific conversion of urea to ammonium ions which facilitates pH-induced aggregation of AuC, leading to fluorescence quenching. This method does not interfere with urease inactive analytes or the autofluorescence of blood as confirmed by comparable urea levels obtained by AuC@Urease and standard clinical methods within an error limit of ±3%.

A label-free protein analysis strategy is based on patterns of gold nanoparticle (AuNP) growth. AuNPs pretreated with different oligonucleotides are challenged with various proteins. After Au reduction, the colorimetric patterns are processed with linear discriminant analysis. This method discriminates different proteins, or one protein of different concentrations, in mixed samples or even serum and urine.

Highly ordered ultra-long oxide nanotubes are fabricated by a simple two-step strategy involving the growth of copper nanowires on nanopatterned template substrates by magnetron sputtering, followed by thermal annealing in air. The formation of such tubular nanostructures is explained according to the nanoscale Kirkendall effect. The concept of this new fabrication route is also extendable to create periodic zero-dimensional hollow nanostructures.

A facile approach to ultrafine hydrophilic polymeric nanoparticles within 10 nm is developed by anhydrous or aqueous inverse microemulsion polymerization of N,N-dimethylacrylamide. Since auto- precipitation of products occurs without any demulsifiers, the recycling of surfactants is feasible. The auto-precipitation mechanism is proposed and discussed. Functionalization of the nanoparticles is achieved by employing them as nanoreactors to form hybrids with titanium tetraisopropoxide.

Single-walled carbon nanotubes (SWNTs) are widely thought to be a strong contender for next-generation printed electronic transistor materials. However, large-scale solution-based parallel assembly of SWNTs to obtain high-performance transistor devices is challenging. SWNTs have anisotropic properties and, although partial alignment of the nanotubes has been theoretically predicted to achieve optimum transistor device performance, thus far no parallel solution-based technique can achieve this. Herein a novel solution-based technique, the immersion-cum-shake method, is reported to achieve partially aligned SWNT networks using semiconductive (99% enriched) SWNTs (s-SWNTs). By immersing an aminosilane-treated wafer into a solution of nanotubes placed on a rotary shaker, the repetitive flow of the nanotube solution over the wafer surface during the deposition process orients the nanotubes toward the fluid flow direction. By adjusting the nanotube concentration in the solution, the nanotube density of the partially aligned network can be controlled; linear densities ranging from 5 to 45 SWNTs/μm are observed. Through control of the linear SWNT density and channel length, the optimum SWNT-based field-effect transistor devices achieve outstanding performance metrics (with an on/off ratio of ~3.2 × 10⁴ and mobility 46.5 cm²/Vs). Atomic force microscopy shows that the partial alignment is uniform over an area of 20 × 20 mm² and confirms that the orientation of the nanotubes is mostly along the fluid flow direction, with a narrow orientation scatter characterized by a full width at half maximum (FWHM) of <15° for all but the densest film, which is 35°. This parallel process is large-scale applicable and exploits the anisotropic properties of the SWNTs, presenting a viable path forward for industrial adoption of SWNTs in printed, flexible, and large-area electronics.

The solution-based immersion-cum-shake method is a novel parallel procedure to achieve partially aligned nanotube networks with controlled areal density. By immersing an aminosilane-treated wafer into a nanotube solution on a rotary shaker, the nanotubes are partially aligned onto the wafer surface. After electrode deposition and isolation, high-performance field-effect transistors with partially aligned single-walled carbon nanotube (SWNT) networks are achieved.

Silicon (Si) has been considered a very promising anode material for lithium ion batteries due to its high theoretical capacity. However, high-capacity Si nanoparticles usually suffer from low electronic conductivity, large volume change, and severe aggregation problems during lithiation and delithiation. In this paper, a unique nanostructured anode with Si nanoparticles bonded and wrapped by graphene is synthesized by a one-step aerosol spraying of surface-modified Si nanoparticles and graphene oxide suspension. The functional groups on the surface of Si nanoparticles (50–100 nm) not only react with graphene oxide and bind Si nanoparticles to the graphene oxide shell, but also prevent Si nanoparticles from aggregation, thus contributing to a uniform Si suspension. A homogeneous graphene-encapsulated Si nanoparticle morphology forms during the aerosol spraying process. The open-ended graphene shell with defects allows fast electrochemical lithiation/delithiation, and the void space inside the graphene shell accompanied by its strong mechanical strength can effectively accommodate the volume expansion of Si upon lithiation. The graphene shell provides good electronic conductivity for Si nanoparticles and prevents them from aggregating during charge/discharge cycles. The functionalized Si encapsulated by graphene sample exhibits a capacity of 2250 mAh g⁻¹ (based on the total mass of graphene and Si) at 0.1C and 1000 mAh g⁻¹ at 10C, and retains 85% of its initial capacity even after 120 charge/discharge cycles. The exceptional performance of graphene-encapsulated Si anodes combined with the scalable and one-step aerosol synthesis technique makes this material very promising for lithium ion batteries.

A unique graphene-bonded and -encapsulated Si nanocomposite synthesized using a one-step aerosol technique exhibits a remarkable cycling stability as anode in a Li ion battery, revealing a promising technology for Si anode development.

A scalable method to coat monochiral (7,5) semiconducting single-walled carbon nanotubes with a monolayer coating of a range of technologically useful polymers such as poly(3-hexylthiophene) (P3HT) and poly(9,9′-dioctylfluorene-co-benzothiadiazole) (F8BT) is presented. Optical spectroscopy and atomic force microscopy measurements show that the semiconducting tube purity (>99%) obtained from the selective wrapping of nanotubes by polymers such as poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) can be transferred to these other nanotube–polymer combinations by polymer exchange.

Graphene oxide (GO) is used as a support for binding with proteins. A GO-based wavelength modulation surface plasmon resonance biosensor shows high sensitivity and selectivity for detection of human immunoglobulin G (IgG). When IgG is coupled with gold nanorods (AuNRs), the size increase results in a refractive index change.

The Watson–Crick base-pairing with specificity and predictability makes DNA molecules suitable for building versatile nanoscale structures and devices, and the DNA origami method enables researchers to incorporate more complexities into DNA-based devices. Thermally controlled atomic force microscopy in combination with nanomechanical spectroscopy with forces controlled in the pico Newton (pN) range as a novel technique is introduced to directly investigate the kinetics of multistrand DNA hybridization events on DNA origami nanopores under defined isothermal conditions. For the synthesis of DNA nanostructures under isothermal conditions at 60 °C, a higher hybridization rate, fewer defects, and a higher stability are achieved compared to room-temperature studies. By quantifying the assembly times for filling pores in origami structures at several constant temperatures, the fill factors show a consistent exponential increase over time. Furthermore, the local hybridization rate can be accelerated by adding a higher concentration of the staples. The new insight gained on the kinetics of staple-scaffold hybridization on the synthesis of two dimensional DNA origami structures may open up new routes and ideas for designing DNA assembly systems with increased potential for their application.

Direct investigation of the kinetics of multistrand DNA hybridization events on DNA origami nanopores under the defined isothermal conditions is performed via thermally controlled atomic force microscopy in combination with nanomechanical spectroscopy, with forces controlled in the pico Newton range.

For ultrathin metallic films (e.g., less than 5 nm), no knowledge is yet available on how electron scattering at surface and grain boundaries reduces the electrical and thermal transport. The thermal and electrical conduction of metallic films is characterized down to 0.6 nm average thickness. The electrical and thermal conductivities of 0.6 nm Ir film are reduced by 82% and 50% from the respective bulk values. The Lorenz number is measured as 7.08 × 10⁻⁸ W Ω K⁻², almost a twofold increase of the bulk value. The Mayadas-Shatzkes model is used to interpret the experimental results and reveals very strong electron reflection (>90%) at grain boundaries.

This work reports the first-time measurement of thermal and electrical conduction of ultra-thin metallic films down to 0.6 nm thickness. Significant reductions of more than 80% for electrical and 50% for thermal conductivities are observed. The ultra-thin film's Lorenz number deviates from the bulk value significantly, with an almost 200% increase. Very strong electron reflection (>90%) at grain boundaries is obtained.

Field emission studies are reported for the first time on layered MoS₂ sheets at the base pressure of ∼1 × 10⁻⁸ mbar. The turn-on field required to draw a field emission current density of 10 μA/cm² is found to be 3.5 V/μm for MoS₂ sheets. The turn-on values are found to be significantly lower than the reported MoS₂ nanoflowers, graphene, and carbon nanotube-based field emitters due to the high field enhancement factor (∼1138) associated with nanometric sharp edges of MoS₂ sheet emitter surface. The emission current–time plots show good stability over a period of 3 h. Owing to the low turn-on field and planar (sheetlike) structure, the MoS₂ could be utilized for future vacuum microelectronics/nanoelectronic and flat panel display applications.

Field emission studies of few-layer MoS₂ sheets show that the turn-on field required to draw a current density of 10 μA/cm² is 3.5 V/μm. The turn-on value is comparable with MoS₂ nanoflower-, graphene-, and carbon nanotube-based field emitters. The low turn-on field value is due to the high field-enhancement factor (∼1138) associated with the nanometric sharp edges of the MoS₂ sheets. It is possible to orient the layered MoS₂ sheets for achieving a higher field enhancement factor, resulting in a high current density obtainable at the lower field.

A new fabrication strategy in which Ag plasmonics are embedded in the interface between ZnO nanorods and a conducting substrate is experimentally demonstrated using a femtosecond-laser (fs-laser)-induced plasmonic ZnO/Ag photoelectrodes. This fs-laser fabrication technique can be applied to generate patternable plasmonic nanostructures for improving their effectiveness in hydrogen generation. Plasmonic ZnO/Ag nanostructure photoelectrodes show an increase in the photocurrent of a ZnO nanorod photoelectrodes by higher than 85% at 0.5 V. Both localized surface plasmon resonance in metal nanoparticles and plasmon polaritons propagating at the metal/semiconductor interface are available for improving the capture of sunlight and collecting charge carriers. Furthermore, in-situ X-ray absorption spectroscopy is performed to monitor the plasmonic-generating electromagnetic field upon the interface between ZnO/Ag nanostructures. This can reveal induced vacancies on the conduction band of ZnO, which allow effective separation of charge carriers and improves the efficiency of hydrogen generation. Plasmon-induced effects enhance the photoresponse simultaneously, by improving optical absorbance and facilitating the separation of charge carriers.

A new fabrication strategy in which Ag plasmonics are embedded in the interface between ZnO nanorods and a conducting substrate is experimentally demonstrated using a femtosecond (fs)-laser-induced ZnO/Ag plasmonic photoelectrode. This fs-laser technique can be applied to generate patternable plasmonic nanostructures for improving their effectiveness in hydrogen generation.

The application of small interfering RNA (siRNA)-based RNA interference (RNAi) for cancer gene therapy has attracted great attention. Gene therapy is a promising strategy for cancer treatment because it is relatively non-invasive and has a higher therapeutic specificity than chemotherapy. However, without the use of safe and efficient carriers, siRNAs cannot effectively penetrate the cell membranes and RNAi is impeded. In this work, cationic poly(lactic acid) (CPLA)-based degradable nanocapsules (NCs) are utilized as novel carriers of siRNA for effective gene silencing of pancreatic cancer cells. These CPLA-NCs can readily form nanoplexes with K-Ras siRNA and over 90% transfection efficiency is achieved using the nanoplexes. Cell viability studies show that the nanoparticles are highly biocompatible and non-toxic, indicating that CPLA-NC is a promising potential candidate for gene therapy in a clinical setting.

Cationic poly(lactic acid) (CPLA)-based degradable nanocapsules (NCs) are utilized as novel carriers of siRNA for effective gene silencing of pancreatic cancer cells. These CPLA-NCs can readily form nanoplexes with K-Ras siRNA and over 90% transfection efficiency is achieved using the nanoplexes.

Traditionally, scanning probe lithography tools are limited in resolution by the radius of curvature of the tip used. Herein, an approach is described for patterning the ridge of piled-up polymer that naturally occurs when a scanning probe is pressed against a soft surface. The use of this phenomenon to transfer patterns to hard materials with 20 nm resolution is demonstrated.

Highly porous hosting materials with conducting (favorable to electron transfer) and magnetic (favorable to product separation) bicontinuous networks should possess great potentials for immobilization of various enzymes in the field of biocatalytic engineering, but the synthesis of such materials is still a great challenge. Herein, bifunctional graphene/γ-Fe₂O₃ hybrid aerogels with quite low density (30–65 mg cm⁻³), large specific surface area (270–414 m² g⁻¹), high electrical conductivity (0.5–5 × 10⁻² S m⁻¹), and superior saturation magnetization (23–54 emu g⁻¹) are fabricated. Single networks of either graphene aerogels or γ-Fe₂O₃ aerogels are obtained by etching of the hybrid aerogels with acid solution or calcining of the hybrid aerogels in air, indicative of the double networks of the as-synthesized graphene/γ-Fe₂O₃ hybrid aerogels for the first time. The resulting bifunctional aerogels are used to immobilize β-glucuronidase for biocatalytic transformation of glycyrrhizin into glycyrrhetinic acid monoglucuronide or glycyrrhetinic acid, with high biocatalytic activity and definite repeatability.

Graphene/γ-Fe₂O₃ hybrid aerogels with conducting (favorable to electron transfer) and magnetic (favorable to product separation) bicontinuous networks are fabricated for the first time and used to immobilize β-glucuronidase for the biocatalytic transformation of glycyrrhizin into glycyrrhetinic acid monoglucuronide or glycyrrhetinic acid, with high biocatalytic activity and definite repeatability.

Alternating voltage-induced electrochemical synthesis (AVIES) produces well-dispersed, size-controlled, single-crystalline, colloidal palladium nanocrystals (Pd-NCs). An alternating voltage is applied to two Pd wires inserted in an electrolyte solution containing capping ligands. Pd-NCs are directly ejected from the Pd electrodes through cathodic reduction of the PdO intermediates. The obtained Pd-NCs are soluble in either polar or non-polar solvents, depending on the selected capping ligands.

3D porous hierarchical Cu₂S microsponges (HCMs) constructed from 2D ultrathin active nanosheets (∼1.5 nm) with nearly 99% exposed (111) facets are fabricated by a simple hydrothermal route. The as-prepared HCMs possess an improved visible-light-harvesting ability, high surface area, low electron–hole recombination, and excellent photocatalytic activity for phenol degradation under visible light irradiation.

A highly flexible and transparent transistor is developed based on an exfoliated MoS₂ channel and CVD-grown graphene source/drain electrodes. Introducing the 2D nanomaterials provides a high mechanical flexibility, optical transmittance (∼74%), and current on/off ratio (>10⁴) with an average field effect mobility of ∼4.7 cm² V⁻¹ s⁻¹, all of which cannot be achieved by other transistors consisting of a MoS₂ active channel/metal electrodes or graphene channel/graphene electrodes. In particular, a low Schottky barrier (∼22 meV) forms at the MoS₂/graphene interface, which is comparable to the MoS₂/metal interface. The high stability in electronic performance of the devices upon bending up to ±2.2 mm in compressive and tensile modes, and the ability to recover electrical properties after degradation upon annealing, reveal the efficacy of using 2D materials for creating highly flexible and transparent devices.

Versatility of using multilayer MoS₂ and graphene to achieve highly flexible and tranparent transistors on a plastic substrate is demonstrated by optical/electrical analyses and stability tests upon mechanical bending.

Binary wettability patterned surfaces with extremely high wetting contrasts can be found in nature on living creatures. They offer a versatile platform for microfluidic management. In this work, a facile approach to fabricating erasable and rewritable surface patterns with extreme wettability contrasts (superhydrophilic/superhydrophobic) on a TiO₂ nanotube array (TNA) surface through self-assembly and photocatalytic lithography is reported. The multifunctional micropatterned superhydrophobic TNA surface can act as a 2D scaffold for site-selective cell immobilization and reversible protein absorption. Most importantly, such a high-contrast wettability template can be used to construct various well-defined 3D functional patterns, such as calcium phosphate, silver nanoparticles, drugs, and biomolecules in a highly selective manner. The 3D functional patterns would be a versatile platform in a wide range of applications, especial for biomedical devices (e.g., high-throughput molecular sensing, targeted antibacterials, and drug delivery). In a proof-of-concept study, the surface-enhanced Raman scattering and antibacterial performance of the fabricated 3D AgNP@TNA pattern, and the targeted drug delivery for site-specific and high-sensitivity cancer cell assays was investigated.

Fabrication of erasable and rewritable superhydrophilic–superhydrophobic patterns on a TiO₂ nanotube array surface is described. The patterned superhydrophobic surface is an excellent 2D scaffold for site-selective cell adhesion and reversible protein absorption, and acts as a template to deposit or grow well-defined 3D spatially functional biomaterials (e.g., CaP, Ag, biological molecules, and drugs), and has potential for use in SERS, antibacterial activity, and targeted drug delivery for high-sensitivity cancer cell bioassays.

A biomimetic quantum dot synthesis-based strategy for ultrasensitive label-free detection of protease activities is reported. A dithiol peptide substrate can be activated by the protease through cleavage to form monothiol peptides, which then triggers QD growth and generates a photoluminescence signal readout. As low as 0.8 nM trypsin can be detected directly in buffer and serum and 4 pM trypsin can be detected via trypsinogen amplification with high signal to background ratios.

A simple method to fabricate a visible light-detectable hybrid nanodevice based on TiO₂ nanoparticles and pristine graphene, ideally combining the advantages of both, is demonstrated. High photosensitivity of the hybrid device under visible and UV light irradiation paves the way for its application as a broad wavelength photodetector.

Matching the scale of microfluidic flow systems with that of microelectronic chips for realizing monolithically integrated systems still needs to be accomplished. However, this is appealing only if such re-scaling does not compromise the fluidic throughput. This is related to the fact that the cost of microelectronic circuits primarily depends on the layout footprint, while the performance of many microfluidic systems, like flow cytometers, is measured by the throughput. The simple operation of inertial particle focusing makes it a promising technique for use in such integrated flow cytometer applications, however, microfluidic footprints demonstrated so far preclude monolithic integration. Here, the scaling limits of throughput-per-footprint (TPFP) in using inertial focusing are explored by studying the interplay between theory, the effect of channel Reynolds numbers up to 1500 on focusing, the entry length for the laminar flow to develop, and pressure resistance of the microchannels. Inertial particle focusing is demonstrated with a TPFP up to 0.3 L/(min cm²) in high aspect-ratio rectangular microfluidic channels that are readily fabricated with a post-CMOS integratable process, suggesting at least a 100-fold improvement compared to previously demonstrated techniques. Not only can this be an enabling technology for realizing cost-effective monolithically integrated flow cytometry devices, but the methodology represented here can also open perspectives for miniaturization of many biomedical microfluidic applications requiring monolithic integration with microelectronics without compromising the throughput.

Integration of microfluidic structures and microelectronic chips is appealing only if the required downscaling for microfluidics does not compromise the fluidic throughput. Here, such integration of microfluidic inertial focusing is feasible by exploring the scaling laws of throughput-per-footprint (TPFP). This study reveals the interplay between theory, the effect of Reynolds numbers between 75 and 1500 on focusing, the entry length for the laminar flow to develop, and pressure resistance of the microchannels, in maximizing TPFP.

Silver nanoparticles (nanosilver) are broadly used today in textiles, food packaging, household devices and bioapplications, prompting a better understanding of their toxicity and biological interactions. In particular, the cytotoxicity of nanosilver with respect to mammalian cells remains unclear, because such investigations can be biased by the nanosilver coatings and the lack of particle size control. Here, nanosilver of well-defined size (5.7 to 20.4 nm) supported on inert nanostructured silica is produced using flame aerosol technology. The cytotoxicity of the prepared nanosilver with respect to murine macrophages is assessed in vitro because these cells are among the first to confront nanosilver upon its intake by mammals. The silica support facilitates the dispersion and stabilization of the prepared nanosilver in biological suspensions, and no other coating or functionalization is applied that could interfere with the biointeractions of nanosilver. Detailed characterization of the particles by X-ray diffraction and electron microscopy reveals that the size of the nanosilver is well controlled. Smaller nanosilver particles release or leach larger fractions of their mass as Ag⁺ ions upon dispersion in water. This strongly influences the cytotoxicity of the nanosilver when incubated with murine macrophages. The size of the nanosilver dictates its mode of cytotoxicity (Ag⁺ ion-specific and/or particle-specific). The toxicity of small nanosilver (<10 nm) is mostly mediated by the released Ag⁺ ions. The influence of such ions on the toxicity of nanosilver decreases with increasing nanosilver size (>10 nm). Direct silver nanoparticle–macrophage interactions dominate the nanosilver toxicity at sizes larger than 10 nm.

The cytotoxicity of nanosilver against macrophages is investigated using precisely size-tuned nanosilver supported on nanostructured silica. Small (<10 nm) nanosilver releases a large fraction of its mass as Ag⁺ ions when compared to large nanosilver (>10 nm). Therefore, the toxicity of small nanosilver is mostly mediated by the released Ag⁺ ions. However, as the nanosilver size increases, direct silver nanoparticle–cell interactions dominate the toxicity.

The widespread potential application of vertically aligned carbon nanotube (CNT) forests have stimulated recent work on large-area chemical vapor deposition growth methods, but improved control of the catalyst particles is needed to overcome limitations to the monodispersity and packing density of the CNTs. In particular, traditional thin-film deposition methods are not ideal due to their vacuum requirements, and due to limitations in particle uniformity and density imposed by the thin-film dewetting process. Here, a continuous-feed convective self-assembly process for manufacturing uniform mono- and multi-layers of catalyst particles for CNT growth is presented. Particles are deposited from a solution of commercially available iron oxide nanoparticles, by pinning the meniscus between a blade edge and the substrate. The substrate is translated at constant velocity under the blade so the meniscus and contact angle remain fixed as the particles are deposited on the substrate. Based on design of the particle solution and tuning of the assembly parameters, a priori control of CNT diameter and packing density is demonstrated. Quantitative relationships are established between the catalyst size and density, and the CNT morphology and density. The roll-to-roll compatibility of this method, along with initial results achieved on copper foils, suggest promise for scale-up of CNT forest manufacturing at commercially relevant throughput.

Continuous-feed evaporative self-assembly is used to create nanoparticle arrays for carbon nanotube (CNT) film growth. This versatile method enables specification of the CNT film morphology, and wide-range tuning of the diameter and density of CNT forests. The present results exceed the performance limits of thin-film catalyst dewetting, and the process is compatible with roll-to-roll manufacturing on flexible substrates.

Cobalt phosphate (CoPi) nanoplates can be integrated with graphene oxide (GO) by photochemical deposition from an aqueous solution under visible-light illumination using GO as a photocatalyst. The use of the CoPi/GO composites as an oxygen-evolving catalyst with high efficiency is demonstrated. Integrating CoPi with GO leads to reduction of the overvoltage and enhancement of the photocurrent.

Carbon nanotubes (CNTs) can penetrate the membranes of cells, offering prospects for nanomedicine but problems for nanotoxicity. Molecular simulations are used to provide a systematic analysis of the interactions of single-walled and multi-walled CNTs of different radii with a model lipid bilayer membrane. The simulations allow characterisation of the mechanism of spontaneous exothermic insertion of CNTs into lipid bilayer membranes. The size and type of CNT determine the nature and extent of the local perturbation of the bilayer. Single-walled CNTs are shown to insert via a two-step mechanism with initial transient formation of a water filled pore followed by full insertion of the CNT into the bilayer. The latter stage is associated with formation of a persistent inverted micelle arrangement of lipid molecules trapped inside the CNT. This suggests a possible vehicle for nano-encapsulation of drugs, enabling their entry into and subsequent release within cells following endocytosis of CNT-containing membranes.

Insertion of carbon nanotubes (CNTs) into lipid membranes is investigated by molecular dynamics simulations. The size and type of CNT determines the bilayer perturbation. Single-walled CNTs insert via a two-step mechanism with formation of a transient water pore followed by a persistent inverted micelle. The latter stage suggests a possible mode of drug encapsulation for delivery into cells.

In contrast to pristine zinc phthalocyanine (1), zinc phthalocyanine based oPPV-oligomers (2–4) of different chain lengths interact tightly and reversibly with graphite, affording stable and finely dispersed suspensions of mono- to few-layer graphene—nanographene (NG)—that are photoactive. The p-type character of the oPPV backbones and the increasing length of the oPPV backbones facilitate the overall π–π interactions with the graphene layers. In NG/2, NG/3, and NG/4 hybrids, strong electronic coupling between the individual components gives rise to charge transfer from the photoexcited zinc phthalocyanines to NG to form hundreds of picoseconds lived charge transfer states. The resulting features, namely photo- and redoxactivity, serve as incentives to construct and to test novel solar cells. Solar cells made out of NG/4 feature stable and repeatable photocurrent generation during several ‘on-off’ cycles of illumination with monochromatic IPCE values of around 1%.

Photoactive graphene hybrids: p-type oligo-para-phenylene vinylene zinc phthalocyanine oligomers exfoliate graphite, interact electronically with wet-chemically exfoliated graphite via charge transfer, and produce photocurrent upon illumination.

A simple strategy is developed to prepare eccentrically or homogeneously loaded nanoparticles (NPs) using poly (DL-lactide-co-glycolide) (PLGA) as the encapsulation matrix in the presence of different amounts of polyvinyl alcohol (PVA) as the emulsifier. Using 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl)-phenyl)amino)-phenyl)-fumaronitrile (TPETPAFN), a fluorogen with aggregation-induced emission (AIE) characteristics, as an example, the eccentrically loaded PLGA NPs show increased fluorescence quantum yields (QYs) as compared to the homogeneously loaded ones. Field emission transmission electron microscopy and fluorescence lifetime measurements reveal that the higher QY of the eccentrically loaded NPs is due to the more compact aggregation of AIE fluorogens that restricts intramolecular rotations of phenyl rings, which is able to more effectively block the non-radiative decay pathways. The eccentrically loaded NPs show far red/near infrared emission with a high fluorescence QY of 34% in aqueous media. In addition, by using poly([lactide-co-glycolide]-b-folate [ethylene glycol]) (PLGA-PEG-folate) as the co-encapsulation matrix, the obtained NPs are born with surface folic acid groups, which are successfully applied for targeted cellular imaging with good photostability and low cytotoxicity. Moreover, the developed strategy is also demonstrated for inorganic-component eccentrically or homogeneously loaded PLGA NPs, which facilitates the synthesis of polymer NPs with controlled internal architectures.

A simple strategy to control the location of fluorogens with aggregation-induced emission (AIE) characteristics in poly (DL-lactide-co-glycolide) (PLGA) nanoparticles is developed by changing the concentration of emulsifier, polyvinyl alcohol (PVA). The AIE fluorogens eccentrically loaded PLGA nanoparticles show a high quantum yield of 34%, good biocompatibility, and a far-red/near infrared fluorescence signature in aqueous conditions, which are ideal for cellular imaging.

Advances in carbohydrate sequencing technologies reveal the tremendous complexity of the glycome and the role that glycomics might have to bring insight into the biological functions. Carbohydrate–protein interactions, in particular, are known to be crucial to most mammalian physiological processes as mediators of cell adhesion and metastasis, signal transducers, and organizers of protein interactions. An assay is developed here to mimic the multivalency of biological complexes that selectively and sensitively detect carbohydrate–protein interactions. The binding of β-galactosides and galectin-3—a protein that is correlated to the progress of tumor and metastasis—is examined. The efficiency of the assay is related to the expression of the receptor while anchoring to the interaction's strength. Comparative binding experiments reveal molecular binding preferences. This study establishes that the assay is robust to isolate metastatic cells from colon affected patients and paves the way to personalized medicine.

A heterogeneous population of cells (tumor and non-tumor cells) seed and come into contact with the substrate, either forming a specific carbohydrate–protein complex or undergoing nonspecific interactions. Only the cells over-expressing galectin-3 and forming specific complex with the substrate are grasped by the microfluidic assay. Multivalency is exploited by a substrate of beads bearing the carbohydrate, permitting an increase in sensitivity of the assay, while specificity is achieved by the equilibrium between the binding and shear forces.

Various annealing conditions (environment, temperature, and duration) are applied to study the nanoscale Kirkendall effect of copper (Cu) nanowire (NW) arrays on a Si substrate. The results show that an appropriate amount of oxygen supply is crucial for uniform transformation from Cu NWs (average diameter ∼50 nm) into Cu oxide nanotube arrays. An annealing duration of 30 min at 200 °C in a low vacuum environment reveals that the voids are not uniformly distributed at the Cu/Cu oxide interface. This suggests that void growth is due to surface diffusion of Cu along void surfaces. Annealing above 200 °C for 60 min resulted in complete transformation from Cu NWs into Cu oxide nanotubes. X-ray photoelectron spectroscopy characterization indicates that the Cu oxides formed at 200 °C and 300 °C are Cu₂O and CuO, respectively. It is demonstrated that the transformation from Cu NW arrays into Cu oxide nanotube arrays can be combined with the joining of stacked Si chips in a single-process step with reasonable joint shear strength. Transmission electron microscopy-electron energy loss spectroscopy elemental mapping analysis reveals that the joint interface is Cu oxide. The outward diffusion of Cu driven by the nanoscale Kirkendall effect is believed to enhance the joining process. By controlling the environment, temperature, and duration, joined Cu₂O or CuO nanotube stacked chips can be achieved, which serve as a platform for the further development of nanostructured, stacked devices.

A Cu nanowire array is transformed into a Cu oxide nanotube array via the nanoscale Kirkendall effect after annealing at 200 °C for 60 min. Coupled with an applied load, this transformation can be used to join two nanostructure array chips in a single processing step. This approach enables the integration of Cu oxide nanotube arrays into a stacked device.

A quantitative understanding of the localized surface plasmon resonances (LSPRs) of metallic nanostructures has received tremendous interest. However, most of the current studies are concentrated on theoretical calculation due to the difficulty in experimentally obtaining monodisperse discrete metallic nanostructures with high purity. In this work, endeavors to assemble symmetric and asymmetric gold nanoparticle (AuNP) dimer structures with exceptional purity are reported using a DNA self-assembly strategy through a one-step gel electrophoresis, which greatly facilitates the preparation process and improves the final purity. In the obtained Au nanodimers, the sizes of AuNPs (13, 20, and 40 nm) and the interparticle distances (5, 10, and 15 nm) are tunable. The size- and distance-dependent plasmon coupling of ensembles of single, isolated dimers in solution are subsequently investigated. The experimental measurements are correlated with the modeled plasmon optical properties of Au nanodimers, showing an expected resonance shift with changing particle sizes and interparticle distances. This new strategy of constructing monodisperse metallic nanodimers will be helpful for building more complicated nanostructures, and our theoretical and experimental understanding of the intrinsic dependence of plasmon property of metallic nanodimer on the sizes and interparticle distances will benefit the future investigation and exploitation of near-field plasmonic properties.

Au nanodimers with tunable sizes and interparticle distances are prepared using a DNA self-assembly strategy through a one-step gel electrophoresis. The size- and distance-dependent plasmon coupling of ensembles of single, isolated dimers in solution are investigated experimentally and theoretically. A quantitative understanding of the intrinsic dependence of plasmon properties of metallic nanodimers on the size and interparticle distance will benefit future investigations and the exploitation of near-field plasmonic properties.

Laser-induced thermal effects in optically trapped microspheres and single cells are investigated by quantum dot luminescence thermometry. Thermal spectroscopy has revealed a non-localized temperature distribution around the trap that extends over tens of micrometers, in agreement with previous theoretical models besides identifying water absorption as the most important heating source. The experimental results of thermal loading at a variety of wavelengths reveal that an optimum trapping wavelength exists for biological applications close to 820 nm. This is corroborated by a simultaneous analysis of the spectral dependence of cellular heating and damage in human lymphocytes during optical trapping. This quantum dot luminescence thermometry demonstrates that optical trapping with 820 nm laser radiation produces minimum intracellular heating, well below the cytotoxic level (43 °C), thus, avoiding cell damage.

During optical trapping of living cells, water absorption causes relevant intracellular heating. Quatum dot fluorescence nanothermometry is used here to evaluate the magnitude of this laser-induced heating (that could be larger than 10 °C for moderate trapping powers) as well as to find routes to minimize it by, for example, an adequate selection of the trapping wavelength.

Control of graphene memory devices using photons, via control of the charge-transfer process, is demonstrated by employing gate-voltage pulses to program/erase the memory elements. The hysteresis in the conductance-gate voltage-dependence of graphene field-effect transistors on a SiO₂ substrate can be greatly enlarged by ultraviolet irradiation in both air and vacuum. An enhanced charge transfer between graphene and its surroundings, induced by ultraviolet illumination, is proposed.

A facile, one-pot method of systematically synthesizing yolk–shell materials with complex compositions is proposed. The spray pyrolysis process for obtaining yolk–shell materials is advantageous because it is highly efficient, allows high throughput, comprises a single-step reaction, and is a continuous process that yields homogeneous composition and enables facile control of the mean size.

Highly localized dislocations in GaN/ZnO hetero-nanostructures are generated from the residual strain field by lattice mismatches at two interfaces: between the substrate and hetero-nanostructures, and between the ZnO core and GaN shell. The local strain field is measured using tranmission electron microscopy, and the relationship between the nanostructure morphology and the highly localized dislocations is analyzed by a finite element method.

Herein a library of hybrid Mn-Anderson polyoxometalates anions are presented: 1, [(MnMo₆O₁₈)((OCH₂)₃-C-(CH₂)₇CHCH₂)₂]³⁻; compound 2, [(MnMo₆O₁₈)((OCH₂)₃C-NHCH₂C₁₆H₉)₂]³⁻; compound 3, [(MnMo₆O₁₈)((OCH₂)₃C-(CH₂)₇CHCH₂)₁((OCH₂)₃C-NHCH₂C₁₆H₉)₁]³⁻; compound 4, [(MnMo₆O₁₈)((OCH₂)₃C-NHC(O)CH₂CHCH₂)₂]³⁻ and compounds 5–9, [(MnMo₆O₁₈)((OCH₂)₃C-NHC(O)(CH₂)_xCH₃)₂]), where x = 4, 10, 12, 14, and 18 respectively. The compounds resulting from the cation exchange of the anions 1–9 to give TBA (a) and DMDOA (b) salts, and additionally for compounds 1, 2 and 3, tetraphenylphosphonium (PPh₄) (c) salts, are explored at the air/water interface using scanning force microscopy, showing a range of architectures including hexagonal structures, nanofibers and other supramolecular forms. Additionally the solid-state structures for compounds 1c, 2c, 4a, 6a, 9a, are presented for the first time and these investigations demonstrate the delicate interplay between the structure of the covalently derivatised hybrid organo-clusters as well as the ion-exchange cation types.

A thorough investigation of nine hybrid Mn-Anderson polyoxometalate self-assembly architectures, both in crystal structures and on surfaces, is carried out. The clusters are obtained with various cations, which influence their self-assembly at interfaces, resulting in structures such as hexagonal nanocrystals, nanofibers, and other supramolecular forms. Using hybrid POMs as building blocks serves as a toolbox for future self-assembly investigations, where a series of variables can be tuned to provide well-defined complex structures.

Circulating tumor cells (CTCs), though exceedingly rare in the blood, are nonetheless becoming increasingly important in cancer diagnostics. Despite this keen interest and the growing number of potential clinical applications, there has been limited success in developing a CTC isolation platform that simultaneously optimizes recovery rates, purity, and cell compatibility. Herein, a novel tracheal carina-inspired bifurcated (TRAB) microfilter system is reported, which uses an optimal filter gap size satisfying both 100% theoretical recovery rate and purity, as determined by biomechanical analysis and fluid–structure interaction (FSI) simulations. Biomechanical properties are also used to clearly discriminate between cancer cells and leukocytes, whereby cancer cells are selectively bound to melamine microbeads, which increase the size and stiffness of these cells. Nanoindentation experiments are conducted to measure the stiffness of leukocytes as compared to the microbead-conjugated cancer cells, with these parameters then being used in FSI analyses to optimize the filter gap size. The simulation results show that given a flow rate of 100 μL min⁻¹, an 8 μm filter gap optimizes the recovery rate and purity. MCF-7 breast cancer cells with solid microbeads are spiked into 3 mL of whole blood and, by using this flow rate along with the optimized microfilter dimensions, the cell mixture passes through the TRAB filter, which achieves a recovery rate of 93% and purity of 59%. Regarding cell compatibility, it is verified that the isolation procedure does not adversely affect cell viability, thus also confirming that the re-collected cancer cells can be cultured for up to 8 days. This work demonstrates a CTC isolation technology platform that optimizes high recovery rates and cell purity while also providing a framework for functional cell studies, potentially enabling even more sensitive and specific cancer diagnostics.

A microfluidic filter system captures circulating tumor cells (CTCs) and distinguishes them from white blood cells (WBCs). It demonstrates maximal recovery rate and purity as determined by biophysical analysis and simulation of fluid–structure interactions. The simulation results are used to optimize the microfluidic filter gap and geometry.

Multicolor emitting microspheres with three dimensionally controlled nanostructures are produced via a simple and efficient method. Location control and separation of the quantum dots (QDs) within the microspheres are achieved by a supramolecular assembly of block copolymer micelles to control the Förster resonance energy transfer efficiency between the different-colored QDs.

Even under heated conditions, the nearly native conformation and activity of a protein can be hoarded in a functionalized nanoporous support via non-covalent interaction. Surprisingly, the protein released from the heated protein–nanoporous composite can maintain its nearly native conformation and activity, while free proteins are permanently denatured under the same treatment.

Assembly into higher-order structures is very important to fully benefit from the extraordinary properties of nanomaterials. SWCNTs are assembled into nanorings using DNA hybridization. The oligonucleotides are covalently attached to the SWCNTs and an oligonucleotide complementary to the oligonucleotides covalently bound to SWCNTs is used to bring assemble them by hybridization.

The development of new electrode materials for lithium-ion batteries (LIBs) has always been a focal area of materials science, as the current technology may not be able to meet the high energy demands for electronic devices with better performance. Among all the metal oxides, tin dioxide (SnO₂) is regarded as a promising candidate to serve as the anode material for LIBs due to its high theoretical capacity. Here, a thorough survey is provided of the synthesis of SnO₂-based nanomaterials with various structures and chemical compositions, and their application as negative electrodes for LIBs. It covers SnO₂ with different morphologies ranging from 1D nanorods/nanowires/nanotubes, to 2D nanosheets, to 3D hollow nanostructures. Nanocomposites consisting of SnO₂ and different carbonaceous supports, e.g., amorphous carbon, carbon nanotubes, graphene, are also investigated. The use of Sn-based nanomaterials as the anode material for LIBs will be briefly discussed as well. The aim of this review is to provide an in-depth and rational understanding such that the electrochemical properties of SnO₂-based anodes can be effectively enhanced by making proper nanostructures with optimized chemical composition. By focusing on SnO₂, the hope is that such concepts and strategies can be extended to other potential metal oxides, such as titanium dioxide or iron oxides, thus shedding some light on the future development of high-performance metal-oxide based negative electrodes for LIBs.

Tin dioxide (SnO₂) is an attractive candidate as a high-capacity anode material for lithium-ion batteries. In this review, a comprehensive discussion is provided about the synthesis of both phase-pure SnO₂ and SnO₂-based nanocomposites with different nanostructures ranging from 1D nanorods, to 2D nanosheets, to 3D hollow structures, and their application in high-performance lithium-ion batteries is discussed.

A nonvolatile analog memory transistor is demonstrated by integrating C60 molecules as charge storage molecules in the transistor gate, and carbon nanotubes (CNTs) in the transistor channel. The currents through the CNT channel can be tuned quantitatively and reversibly to analog values by controlling the number of electrons trapped in the C60 molecules. After tuning, the electrons trapped in the C60 molecules in the gate, and the current through the CNT channel, can be preserved in a nonvolatile manner, indicating the characteristics of the nonvolatile analog memory.

A nonvolatile analog memory transistor is demonstrated by integrating C60 molecules as charge storage molecules in the transistor gate, and carbon nanotubes (CNTs) as the transistor channel. The currents through the CNT channel can be tuned quantitatively and then preserved to analog values by controlling the number of electrons trapped in the C60 molecules.

Plasmonic nanoparticles have traditionally been associated with relatively narrow absorption profiles. But, for many of the most exciting potential applications for these particles, such as solar energy applications, broadband absorption is desirable. By utilizing on-wire lithography, nanostructures which absorb light through the visible and near-IR portions of the electromagnetic spectrum can be synthesized.

An electrohydrodynamic atomization (EHDA) system that generates an electrospray can achieve particle formation and encapsulation by accumulating an electric charge on liquid flowing out from the nozzle. A novel coaxial EHDA system for continuous fabrication of water-stable magnetic nanoparticles (MNPs) is established, based on a cone-jet mode of electrospraying. Systemic variables, such as flow rates from dual nozzles and inducing voltages, are controlled to enable the preparation of water-soluble MNPs coated by polysorbate 80. The PEGylated MNPs exhibit water stability. The magnetic resonance imaging potential of these MNPs is confirmed by in vivo imaging using a gastric cancer xenograft mouse model. Thus, this advanced coaxial EHDA system demonstrates remarkable capabilities for the continuous encapsulation of MNPs to render them water-stable while preserving their properties as imaging agents.

A cone-jet mode of electrospraying is applied in an electrohydrodynamic atomization system with coaxial nozzle for the continuous fabrication of water-stable magnetic nanoparticles (MNPs). The magnetic resonance imaging potential of MNPs coated by polysorbate 80 is confirmed by in vivo imaging of a gastric cancer xenograft mouse model.

SnO₂ tube-in-tube nanostructures are synthesized using Cu@C nanocables as effective sacrificial templates. It is revealed by stripping voltammetry that SnO₂ tube-in-tube nanostructures show excellent performances in the determination of heavy metal ions, which might be related to the extraordinary adsorbing capacities of the hollow structure to metal ions, i.e., metal ions could diffuse into the interior of tubular structure.

A fluorescence method for protein detection is developed based on terminal protection of small-molecule-linked DNA by target protein and a graphene oxide-assisted DNA assay strategy. This design results in fluorescence-enhanced detection that is sensitive and selective for the target protein.

Silica nanorods (SNRs) are synthesized and then functionalized with aminoalkoxysilanes to prepare a new class of nitric oxide (NO)-releasing materials. The aspect ratio and size of the SNRs are tuned by varying the temperature, pH, and silane concentration used during the surfactant-templated synthesis. N-Diazeniumdiolate nitric oxide (NO) donors are formed on the secondary amine-functionalized SNRs by reaction with NO gas under basic conditions. Particle surface modifications are employed to manipulate the NO release kinetics. The diverse morphology (i.e., aspect ratio ∼1–8), NO-release kinetics (2000–14 000 ppb NO/mg particle) and similar sizes (i.e., particle volume ∼0.02 μm³) of the resulting NO-releasing SNRs facilitates further studies of how particle shape and NO flux impacts bactericidal activity against Gram–positive Staphylococcus aureus (S. aureus) and Gram–negative Pseudomonas aeruginosa (P. aeruginosa) bacteria. The bactericidal efficacies of these materials improves with increasing particle aspect ratio and initial NO flux. Both chemical (i.e., NO-release kinetics) and physical (i.e., morphology) properties greatly influenced the bactericidal activity of these materials.

Nitric oxide (NO)-releasing silica nanorods (SNRs) are synthesized with different aspect ratios and NO-release kinetics. The antibacterial efficacy of the SNRs is evaluated against both Gram–positive and –negative bacteria, and depend on both the particle shape and NO-release kinetics.

The production of bone-forming osteogenic cells for research purposes or transplantation therapies remains a significant challenge. Using planar polycarbonate substrates lacking in topographical cues and substrates displaying a nanotopographical pattern, mesenchymal differentiation of human embryonic stem cells is directed in the absence of chemical factors and without induction of differentiation by embryoid body formation. Cells incubated on nanotopographical substrates show enhanced expression of mesenchymal or stromal markers and expression of early osteogenic progenitors at levels above those detected in cells on planar substrates in the same basal media. Evidence of epithelial-to-mesenchymal transition during substrate differentiation and DNA methylation changes akin to chemical induction are also observed. These studies provide a suitable approach to overcome regenerative medical challenges and describe a defined, reproducible platform for human embryonic stem cell differentiation.

Nanopits direct mesenchymal differentiation of human embryonic stem cells in the absence of chemical cues. Cells incubated on a near-square arrangement of nanopits show enhanced expression of mesenchymal and stromal cell markers such as STRO-1. Reciprocal expression of E-cadherin and N-cadherin provide evidence of an epithelial-to-mesenchymal transition during nanotopographical differentiation.

A gold nanotip array platform with a combination of ultrasensitive electrochemical sensing and spectroscopic monitoring capability is reported. Adenosine triphosphate is detected down to 1 pM according to the impedance changes in response to aptamer-specific binding. Furthermore, the local molecular information can be monitored at the individual plasmonic nanotips, and hence provide the capability for a better understanding of complex biological processes.

Strong enhancing effect of plasmonic Au nanoparticles on the photoelectrochemical performance of a ZnFe₂O₄/ZnO heterojunction used as photoanode for water splitting application is demonstrated. The material properties of Au/ZnFe₂O₄/ZnO complement each other remarkably well in the configuration proposed in terms of their optical, electronic, and catalytic properties.

An electrochemical synthesis is developed through quantitative electrochemical reaction of N-alkylcarbazole leading to a novel class of structurally interconnected high-C₆₀ content (60 wt%) polymer films with negligible doping and intrinsic physicochemical properties of pure C₆₀. This strategy allows preparation of previously unavailable low-doped fullerene-containing non-conjugated polymers and broadens the potential applications of electrochemical synthesis for controlled polymer film structures.

Monolayers of polymer-encapsulated Au nanoparticles with controlled density are obtained via a facile solution-based method by modulating the inter-particle repulsion and using empty polymer micelles as spacers. These Au nanoparticles are then used to catalyze the vapor transport growth of metal oxide nanowires, where distinct density-dependent growth regimes are identified.

The ability to map multiple biomarkers at the same time has far-reaching biomedical and diagnostic applications. Here, a series of biocompatible poly(d,l-lactic-co-glycolic acid) and polyethylene glycol particles for multicolor and multiplexed imaging are reported. More than 30 particle formulations that exhibit distinct emission signatures (ranging from the visible to NIR wavelength region) are designed and synthesized. These particles are encapsulated with combinations of carbocyanine-based fluorophores DiO, Dil, DiD, and DiR, and are characterized as <100 nm in size and brighter than commercial quantum dots. A particle formulation is identified that simultaneously emits fluorescence at three different wavelengths upon a single excitation at 485 nm via sequential and multiple FRET cascade events for multicolor imaging. Three other particles that display maximum fluorescence intensities at 570, 672, or 777 nm for multiplexed imaging are also identified. These particles are individually conjugated with specific (Herceptin or IgG2A11 antibody) or nonspecific (heptaarginine) ligands for targeting and, thus, could be applied to differentiate different cancer cells from a cell mixture according to the expressions of cell-surface human epidermal growth factor receptor 2 and the receptor for advanced glycation endproducts. Using an animal model subcutaneously implanted with the particles, it is further demonstrated that the developed platform could be useful for in vivo multiplexed imaging.

Polymeric nanoparticles with distinct emission outputs are developed by the encapsulation of two or more complementary organic fluorophores inside an optically inert matrix. Simply by changing the identity, amount, and ratio of the doped fluorophores, the particles with either single or multiple emission signatures are fine-tuned for multicolor and multiplexed imaging applications.

Methods for the continuous monitoring and removal of ultra-trace levels of toxic inorganic species (e.g., mercury, copper, and cadmium ions) from aqueous media such as drinking water and biological fluids are essential. In this paper, the design and engineering of a simple, pH-dependent, micro-object optical sensor is described based on mesoporous aluminosilica pellets with an adsorbed dressing receptor (a porphyrinic chelating ligand). This tailor-made optical sensor permits ultra-fast (≤ 60 s), specific, pH-dependent visualization and removal of Cu²⁺, Cd²⁺, and Hg²⁺ at sub-picomolar concentrations (∼10⁻¹¹ mol dm⁻³) from aqueous media, including drinking water and a suspension of red blood cells. The acidic active acid sites of the pellets consist of heteroatoms arranged around uniformly shaped pores in 3D nanoscale gyroidal mesostructures densely coated with the chelating ligand. The sensor can be used in batch mode, as well as in a flow-through system in which sampling, target ion recognition and removal, and analysis are integrated in a highly automated and efficient manner. Because the pellets exhibit long-term stability, reproducibility, and versatility over a number of analysis/regeneration cycles, they can be expected to be useful for the fabrication of inexpensive sensor devices for naked-eye detection of toxic pollutants.

A simple, micro-object optical sensor is engineered based on mesoporous aluminosilica pellets with an adsorbed dressing receptor. This tailor-made optical sensor permits ultra-fast (≤60 s), specific, pH-dependent visualization and removal of ultra-trace concentrations (∼10⁻¹¹ mol dm⁻³) from aqueous media. Pellet-based micro-object sensing devices can be expected to be important for use in portable and remote sensing systems, especially for household use, where instrumental methods are prohibitively expensive.

Stem-loop oligonucleotides tagged with organic dyes are employed as capture and reporter probes in a molecular beacon-based signal-off surface- enhanced Raman scattering (SERS) strategy. DNA strands are immobilized on a gold nanoparticle-decorated silicon nanowire array (AuNPs@SiNWAr). DNA with a concentration down to ≈10 fM is detected under irradiation from a low-power laser, which is better than or comparable to that detected by signal-on SERS methods. The signal-off strategy allows identification of single-base mismatches and detection of multiplexed DNA.

Graphene materials can deplete essential micronutrients from cell culture media and potentially interfere with probe dyes used during in vitro analysis of cell viability and function by (1) adsorbing dyes before they can interact with their target biomolecule, (2) quenching fluorescence after the interaction, and/or (3) absorbing or scattering light, which are issues for both colorimetric and fluorescent assays.

Unlike the sharp melting behavior of DNA-linked nanoparticle aggregates, the melting of DNA strands from individual gold nanoparticles is broad despite the high surface density of bound DNA. Here, it is demonstrated how sharpened melting can be achieved in colloidal nanoparticle systems using branched DNA–doubler structures hybridized with complementary DNA-doublers bound to the gold nanoparticle. Moreover, sharpened transitions are observed when DNA-doublers are hybridized with linear DNA-modified gold nanoparticles. This result suggests that the DNA density on nanoparticles is intrinsically great enough to form cooperative structures with the DNA-doublers. Finally, by introducing abasic destabilizing groups, the melting temperature of these DNA-doublers decreases without decreasing the sharpness. Consequently, by varying the temperature, two DNA-doublers with different stabilities dissociate sequentially from the gold nanoparticle surface, without overlapping and within a narrow temperature window. Owing to the excellent thermal selectivities exhibited by this system, the implementation of DNA-doublers in sequential photothermal therapies and with other nanomedicine delivery agents that rely on DNA dissociation as the mechanism of selective release is anticipated.

Branched DNA structures lead to sharp melting behavior when hybridized to DNA-modified gold nanoparticles. Using a mixture of branched DNA with different stabilities, sequential thermal release from a single nanoparticle can be achieved. Unlike linear DNA, the branched DNA exhibits much greater thermal discrimination, so no overlap in the release profile is observed.

A novel light-operated vehicle for targeted intracellular drug delivery is constructed using photosensitizer-incorporated G-quadruplex DNA-capped mesoporous silica nanoparticles. Upon light irradiation, the photosensitizer generates ROS, causing the DNA capping to be cleaved and allowing cargo to be released. Importantly, this platform makes it possible to develop a drug-carrier system for the synergistic combination of chemotherapy and PDT for cancer treatment with spatial/temporal control. Furthermore, the introducing of targeting ligands further improves tumor targeting efficiency. The excellent biocompatibility, cell-specific intracellular drug delivery, and cellular uptake properties set up the basis for future biomedical application that require in vivo controlled, targeted drug delivery.

A novel light-operated vehicle for targeted intracellular drug delivery is constructed using photosensitizer-incorporated G-quadruplex DNA-capped mesoporous silica nanoparticles. Upon light irradiation, the photosensitizer generates ROS, causing the DNA capping to be cleaved and allowing cargo to be released. Importantly, this platform makes it possible to develop a drug-carrier system for the synergistic combination of chemotherapy and PDT for cancer treatment with spatial/temporal control.

Gold nanoparticles (AuNPs) are widely used as carriers or therapeutic agents due to their great biocompatibility and unique physical properties. Transforming growth factor-beta 1 (TGF-β1), a member of the cysteine-knot structural superfamily, plays a pivotal role in many diseases and is known as an immunosuppressive agent that attenuates immune response resulting in tumor growth. The results reported herein reflect strong interactions between TGF-β1 and the surface of AuNPs when incubated with serum-containing medium, and demonstrate a time- and dose-dependent pattern. Compared with other serum proteins that can also bind to the AuNP surface, AuNP–TGFβ1 conjugate is a thermodynamically favored compound. Epithelial cells undergo epithelial–mesenchymal transition (EMT) upon treatment with TGF-β1; however, treatment with AuNPs reverses this effect, as detected by cell morphology and expression levels of EMT markers. TGF-β1 is found to bind to AuNPs through S–Au bonds by X-ray photoelectron spectroscopy. Fourier transform infrared spectroscopy is employed to analyze the conformational changes of TGF-β1 on the surface of AuNPs. The results indicate that TGF-β1 undergoes significant conformational changes at both secondary and tertiary structural levels after conjugation to the AuNP surface, which results in the deactivation of TGF-β1 protein. An in vivo experiment also shows that addition of AuNPs attenuates the growth of TGF-β1-secreting murine bladder tumor 2 cells in syngeneic C3H/HeN mice, but not in immunocompromised NOD-SCID mice, and this is associated with an increase in the number of tumor-infiltrating CD4⁺ and CD8⁺ T lymphocytes and a decrease in the number of intrasplenic Foxp3(+) lymphocytes. The findings demonstrate that AuNPs may be a promising agent for modulating tumor immunity through inhibiting immunosuppressive TGF-β1 signaling.

Dysfunction of transforming growth factor-beta 1 (TGF-β1) by gold nanoparticles (AuNPs) attenuates tumor growth due to conformational changes at both the secondary and tertiary structures. In vivo, the amounts of CD4⁺ and CD8⁺ T lymphocytes increase and the tumor volume decreases in the presence of AuNPs, which is evidence of immune-response recovery through inhibiting immunosuppressive TGF-β1 signaling.

A novel adaptive electrode fabrication method using optically self-selected interfacial adhesion between a laser-processed metal layer and polymer film is introduced to fabricate cost-effectively a high-resolution arbitrary electrode with high conductivity. The quality is close to that from vacuum deposition on a highly heat sensitive polymer film, with active response to various design requirements. A highly conductive metal film (resistivity: 3.6 μΩ cm) below a 5 μm line width with a uniform stepwise profile and mirror surface quality (R_rms: 5–6 nm) is fabricated on a cheap polymer film with a heat resistance limit of below 100 °C. Severe durability tests are successfully completed without using any adhesion promoters. Finally, a highly transparent and conductive electrode with a transparency above 95% and sheet resistance of less than 10 Ω sq⁻¹ is fabricated on a polymer film and on glass by using this method. These results can help realize a potential high-throughput, low-cost, solution-processable replacement for transparent conductive oxides.

Optically self-selected interfacial adhesion based on metal nano-farming from a particle-free metallic solution is used to fabricate a high-resolution electrode, with performance and quality close to those obtained by vacuum deposition, on a heat-sensitive flexible film. This method could be an alternative to conventional vacuum and printing processes for transparent conductor fabrication.

Patterned reduced graphene oxide (rGO) films with vertically aligned tip structures are fabricated by a straightforward self-assembly method. The size, uniformity of the patterns, and alignment of the tips are successfully controlled according to the concentration of a GO/octadecylamine (ODA)-dispersed solution. The surface energy difference between the GO/ODA solution and a self-assembled water droplet is a critical parameter for determining the pattern structure. Numerous rGO nanosheets are formed so as to be vertically aligned with respect to the substrate during film fabrication at GO concentrations below 2.0 g/L. These samples provide high field-emission characteristics. The patterned rGO arrays are highly flexible with preservation of the field emission properties, even at large bending angles. This is attributed to the high crystallinity, emitter density, and good chemical stability of the rGO arrays, as well as the strong interactions between the rGO arrays and the substrate.

Self-organized graphene nanosheets with corrugated, ordered tip structures ae fabricated by a straightforward self-assembly method. The size, uniformity of the arrays, and alignment of tips are successfully controlled by the viscosity of the graphene oxide/octadecylamine solution. The vertically aligned tip structures of graphene thin films fabricated on polymeric substrate show excellent field emission characteristics upon bending.

In biological environments, nanomaterials associate with proteins forming a protein corona (PC). The PC may alter the nanomaterial's pharmacokinetics and pharmacodynamics, thereby influencing toxicity. Using a label-free mass spectrometry-based proteomics approach, the composition of the PC is examined for a set of nanotubes (NTs) including unmodified and carboxylated single- (SWCNT) and multi-walled carbon nanotubes (MWCNT), polyvinylpyrrolidone (PVP)-coated MWCNT (MWCNT-PVP), and nanoclay. NTs are incubated for 1 h in simulated cell culture conditions, then washed, resuspended in PBS, and assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for their associated PC. To determine those attributes that influence PC formation, the NTs are extensively characterized. NTs had negative zeta potentials in water (SWCNT-COOH < MWCNT-COOH < unmodified NTs) while carboxylation increases their hydrodynamic sizes. All NTs are also found to associate a common subset of proteins including albumin, titin, and apolipoproteins. SWCNT-COOH and MWCNT-COOH are found to bind the greatest number of proteins (181 and 133 respectively) compared to unmodified NTs (<100), suggesting covalent binding to protein amines. Modified NTs bind a number of unique proteins compared to unmodified NTs, implying hydrogen bonding and electrostatic interactions are involved in PC formation. PVP-coating of MWCNT did not influence PC composition, further reinforcing the possibility of hydrogen bonding and electrostatic interactions. No relationships are found between PC composition and corresponding isoelectric point, hydropathy, or aliphatic index, implying minimal roles of hydrophobic interaction and pi-stacking.

Nanomaterials associating with proteins form a protein corona which may affect their toxicity. Through a novel proteomics approach, this study determines distinct protein corona formations on a variety of carbon-based nanotubes. Protein and nanotube characteristics which may facilitate these interactions are evaluated. The results suggest differential protein corona composition based on functionalization and purity of nanotubes.

A Pd nanoparticle-containing polymer microsphere moves with increasing speed across a pH gradient, following differential catalytic decomposition of aqueous hydrogen peroxide. The directional motion is akin to the pH taxis of living microorganisms. The artificial pH taxis exhibits random walk, translation, vertical, hopping, and pulsed motion, when the size of the motor and the imposed pH gradient are modulated.

Site-specific silica encapsulation of the CdSe core region of CdSe/CdS tetrapods is employed to allow for the fluorescence from the CdSe core to be preserved during the growth of secondary functional materials, which is exploited to achieve Ag₂S-tipped SiO₂-CdSe/CdS tetrapods with dual emission at visible and IR wavelengths and Au/Fe_xO_y-tipped SiO₂-CdSe/CdS tetrapods which exhibits both fluorescence and a strong magnetic response.

The production of multi-compartmented particles for biomedical and biotechnological applications is challenging and the existing methods usually involve wet and aggressive conditions that compromise the encapsulation efficiency of bioactive agents and the viability of cells. Biomimetic superhydrophobic surfaces allow construction of concentric multilayered polymeric systems, adding sequential layers where molecules or cells may be separately confined in compartments with high efficiency.

A hierarchically patterned metal/semiconductor (gold nanoparticles/ZnO nanowires) nanostructure with maximized photon trapping effects is fabricated via interference lithography (IL) for plasmon enhanced photo-electrochemical water splitting in the visible region of light. Compared with unpatterned (plain) gold nanoparticles-coated ZnO NWs (Au NPs/ZnO NWs), the hierarchically patterned Au NPs/ZnO NWs hybrid structures demonstrate higher and wider absorption bands of light leading to increased surface enhanced Raman scattering due to the light trapping effects achieved by the combination of two different nanostructure dimensions; furthermore, pronounced plasmonic enhancement of water splitting is verified in the hierarchically patterned Au NPs/ZnO NWs structures in the visible region. The excellent performance of the hierarchically patterned Au NPs/ZnO NWs indicates that the combination of pre-determined two different dimensions has great potential for application in solar energy conversion, light emitting diodes, as well as SERS substrates and photoelectrodes for water splitting.

A hierarchically patterned metal/semiconductor nanostructure is fabricated via interference lithography for plasmon-enhanced photoelectrochemical water splitting in the visible region of light. Compared with unpatterned Au NPs/ZnO NWs, the hierarchically patterned structures demonstrate higher and wider absorption bands leading to increased surface enhanced Raman scattering and surface plasmon-enhanced water splitting.

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double-stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double-stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor-mediated internalization should enhance the therapeutic effect of the siRNA-mediated cancer therapy.

A multifunctional siRNA delivery nanoparticle platform that combines the imaging capability of the nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA-expressing DNA nanocassettes is developed. The ability to express siRNA from multiple nanocassettes conjugated to each nanoparticle following receptor-mediated internalization enhances the effect of gene silencing in tumor cells and in an animal tumor model.

The plasmon-mediated synthesis of silver nanoparticles is a versatile synthetic method which leverages the localized surface plasmon resonance (LSPR) of nanoscale silver to generate particles with non-spherical shapes and control over dimensions. Herein, a method is reported for controlling the twinning structure of silver nanoparticles, and consequently their shape, via the plasmon-mediated synthesis, solely by varying the excitation wavelength between 400, 450, and 500 nm, which modulates the rate of Ag⁺ reduction. Shorter, higher energy excitation wavelengths lead to faster rates of reaction, which in turn yield structures containing a greater number of twin boundaries. With this method, silver cubes can be synthesized using 450 nm excitation, which represents the first time this shape has been realized by a plasmon-mediated synthetic approach. In addition, these cubes contain an unusual twinning structure composed of two intersecting twin boundaries or multiple parallel twin boundaries. With respect to their twinning structure, these cubes fall between planar-twinned and multiply twinned nanoparticles, which are synthesized using 500 and 400 nm excitation, respectively.

A plasmon-mediated synthesis of twinned silver cubes using 450 nm excitation is reported. The cubes possess multiple twin boundaries arranged in either a parallel or intersecting orientation. In addition, the twin structure of the silver particles synthesized via this method can be controlled solely by varying the excitation wavelength to adjust reaction kinetics.

Graphene oxide (GO) has been extensively explored in nanomedicine for its excellent physiochemical, electrical, and optical properties. Here, polyethylene glycol (PEG) and polyethylenimine (PEI) are covalently conjugated to GO via amide bonds, obtaining a physiologically stable dual-polymer-functionalized nano-GO conjugate (NGO-PEG-PEI) with ultra-small size. Compared with free PEI and the GO-PEI conjugate without PEGylation, NGO-PEG-PEI shows superior gene transfection efficiency without serum interference, as well as reduced cytotoxicity. Utilizing the NIR optical absorbance of NGO, the cellular uptake of NGO-PEG-PEI is shown to be enhanced under a low power NIR laser irradiation, owing to the mild photothermal heating that increases the cell membrane permeability without significantly damaging cells. As the results, remarkably enhanced plasmid DNA transfection efficiencies induced by the NIR laser are achieved using NGO-PEG-PEI as the light-responsive gene carrier. More importantly, it is shown that our NGO-PEG-PEI is able to deliver small interfering RNA (siRNA) into cells under the control of NIR light, resulting in obvious down-regulation of the target gene, Polo-like kinase 1 (Plk1), in the presence of laser irradiation. This study is the first to use photothermally enhanced intracellular trafficking of nanocarriers for light-controllable gene delivery. This work also encourages further explorations of functionalized nano-GO as a photocontrollable nanovector for combined photothermal and gene therapies.

PEG and PEI dual-functionalized ultra-small graphene oxide (NGO-PEG-PEI) with excellent physiologial stability against salts and serum is explored as a gene delivery carrier, which exhibits superior gene transfection efficiency even in the presence of serum, as well as an exciting photothermally controlled gene therapy potential under mild NIR laser irradiation.