Efficient and safe gene transfection carriers, especially for hard-to-transfect cells, are urgently demanded in basic biological research and gene therapy applications. Many insect cell lines widely used in molecular cell biology exhibit relatively low transfection efficiencies when treated by conventional non-viral agents. Herein, we develop a novel gene delivery vector by coating graphene oxide (GO) with both polyethylene glycol (PEG) and polyethylenimine (PEI), obtaining a dual-polymer-functionalized nanoscale GO (nGO-PEG-PEI) to transfect insect cells. While exhibiting remarkably reduced cytotoxicity compared with PEI, nGO-PEG-PEI, when used as the plasmid DNA transfection agent to treat Drosophila S2 cells, offers ≈7-fold and ≈2.5-fold higher efficiency compared with those achieved by using bare PEI and Lipofectamine 2000, a widely used commercial transfection agent, respectively. Interestingly, the advantages of nGO-PEG-PEI are even more dramatic when transfecting cells with lower-quality linearized DNA. It is revealed that nGO-PEG-PEI/pDNA complexes enter insect cells via a unique pathway working even at a low temperature, rather different from their entry into mammalian adherent cells. Our results encourage the development of nano-GO-based gene carriers to treat special types of hard-to-transfect cells (e.g., insect cells), and indicate that nanomaterials would enter cells by cell-type-dependent mechanisms, which merit significantly more future attentions.

Silica nanoparticles (SiO₂ NPs) are one of the most widely used engineered nanoparticles and can been found in a wide range of consumer products. Despite their massive global production scale, little is known about their potential effects in the context of unintended exposure or ingestion. Using TR146 cells as an in vitro model of the human oral buccal mucosa, the uptake, spatial intracellular distribution, reactive oxygen species (ROS) production, inflammatory response, and cytotoxic effects of commercial SiO₂ NPs are examined. SiO₂ NPs are shown to dock and cross the cellular membrane barrier in a dose–time-dependent manner. Confocal sectioning reveals translocation of SiO₂ NPs into the cell nucleus after 12 h of exposure. A concentration threshold of more than 500 × 10⁻⁶ m is observed, above which SiO₂ NPs are shown to exert significant oxidative stress with concomitant upregulation of inflammatory genes IL6 and TNFA. Further analysis of the p53 pathway and a series of apoptotic and cell cycle biomarkers reveals intracellular accumulation of SiO₂ NPs exert marginal nanotoxicity. Collectively, this study provides important information regarding the uptake, intracellular distribution, and potential adverse cellular effects of SiO₂ NPs commonly found in consumer products in the human oral epithelium.

Photonic effects amplifying solar energy conversion are reported in titania inverse opals sensitized with quantum-confined CdSe films. TiO₂ inverse opals (i-TiO₂-o) and unstructured nanocrystalline TiO₂ (nc-TiO₂) films are sensitized with CdSe deposited via successive ionic layer adsorption and reaction (SILAR) by generating Se²⁻ in situ under inert atmosphere, and the film absorbance is tuned by the number of SILAR cycles. Photonic effects are investigated while varying the i-TiO₂-o stop band position relative to CdSe films’ absorbance. i-TiO₂-o films with stop band at 700 and 560 nm are sensitized with CdSe having absorption edges at 600 and 650 nm thus tuning absorbance to the red and the blue of the stop band. Significant amplification in photon-to-current conversion efficiency is measured when CdSe films prepared via two cycles are adsorbed on i-TiO₂-o with a stop band at 700 nm, with a maximum average enhancement factor equal to 6.7 ± 1.6 at 640 nm, 60 nm to the blue of the stop band center, relative to nc-TiO₂ sensitized with comparable CdSe amounts. The gain is observed over a wide frequency range to the blue of the stop band and is greatest when film absorbance was low. The photocurrent gain is not a result of differences in the rates of charge separation or charge transport, and occurs in the same frequency range where absorbance amplification is measured to the blue of the 700-i-TiO₂-o stop band, and is thus attributed to slow light effects enhancing absorbance in the photonic crystal environment.

Hierarchical carbon-encapsulated iron nanoparticles (Fe@Cs) with typical core/shell structure are successfully synthesized from starch and iron nitrate by an easy-to-handle process at different carbonization temperatures (600–1000 °C). The nanoparticles are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption, and Fourier transform infrared spectroscopy (FTIR). The results show that the carbonization temperature has an important effect on the morphology, the core shape, the diameters, and the porous structure as well as performance of Fe@Cs. Fe@C samples carbonized at 900 °C (Fe@C-900) show the relatively perfect quasi-spherical bcc-Fe core/carbon shell porous structure and their diameters are in a narrow range of 20–50 nm. The adsorption capabilities of Fe@C samples obtained at different carbonization temperatures for removal of thiophene from model oils are evaluated and compared in a batch-type adsorption system. It has been found that among all of the samples measured, Fe@C-900 shows the highest adsorption capability with an increase of 54% for thiophene in comparison with that of the commercial activated carbon. The feasibility of the as-prepared Fe@C-900 as a magnetically separable adsorbent is also demonstrated.

The heterogeneous assembly of colloidal polymer particles on the nano- and microstructures of a metal is a versatile platform for adjusting the mechanical and electrical properties simultaneously. The assemblies of silver (Ag) microrods and flower-like zinc oxide (ZnO) microparticles with poly(methyl methacrylate) (PMMA) nanospheres are presented to prepare advanced composite materials. PMMA nanoparticles are prepared via the emulsion polymerization technique using a microfluidic preparation step in the presence of cationic surfactant. The surface charge of PMMA particles determines the binding interaction strength with inorganic constituents. Ag microrods and ZnO microparticles are prepared in a batch and in a continuous flow process, respectively. The assembling process can be explained by a particle–particle binding process due to the electrostatic interaction for both types of nanoassemblies. The observed binding pattern reveals certain lateral mobility of the small polymer particles at the surface of larger metal particle. The particle ratios in the nanoassemblies can be tuned over a wide range by changing the reaction parameters.

The ultrasound-assisted self-assembly and cross-linking of lysozyme at the water–air and water–perfluorohexane interfaces are shown to produce lysozyme-shelled hollow microbubbles (LSMBs) and microcapsules (LSMC), respectively. The arrangement of lysozyme at the air–liquid or oil–liquid interfaces is accompanied by changes in the bioactivity and conformational state of the protein. The interaction of LSMB and LSMC with human breast adenocarcinoma cells (SKBR3) is studied. LSMB and LSMC are phagocyted by cells within 2 h without exerting a cytotoxic activity. The cellular internalization kinetics of LSMB and LSMC and the effects on cell cycle are evaluated using flow cytometry. Evidence for the internalization of microparticles and degradation within the cell are also monitored by confocal and scanning electron microscopic analyses. The integrity of cell membrane and cell cycle is not affected by LSMBs and LSMCs uptake. These studies show that the positively charged LSMB and LSMC are not cytotoxic and can be readily internalized and degraded by the SKBR3 cells. LSMBs and LSMCs show a different uptake kinetics and intracellular degradation pattern due to differences in the arrangement of the protein at the air–liquid or oil–liquid interfaces.

Super crystallization of ligand-capped nanocrystals into defined periodic solids from solution is the definitive demonstration of their self-organizing properties. To date, this has been mainly limited to spherical nanocrystals where organization emulates atom or molecule packing in regular crystals with the most thermodynamically stable arrangement being eventually preferred. Here, the crystallization of wurtzite CdS nanorods into micrometer-sized CdS superstructures with regular hexagonal symmetry is demonstrated by fine-tuning the nanorod dispersibility over time. It is shown that the supercrystals have a long nucleation stage to form monolayer hexagons followed by a relatively faster growth stage both occurring rod by rod (in-plane) and layer by layer (out of plane). The perfectly symmetrical hexagon shape of the final structure is mapped from the wurtzite crystal structure of each individual nanorod where they pack in side by side and end to end arrangements. These well-defined superstructures are highly attractive for applications that collectively exploit electronic or optical properties that are synthetically tunable through the size and shape of each nanorod building block.

The synthesis of silica-based colloidosomes with a polymer core obtained via inverse Pickering emulsification and their use as an implantable drug delivery system in zebrafish are described. Silica nanoparticles act as a stabilizer of a water-in-oil emulsion creating aqueous droplets with a silica shell. The core of the colloidosomes is polymerized resulting in tough particles. Colloidosomes loaded with model drugs show a release profile dependent on the porosity of the silica nanoparticles. Studying the effect of drugs on zebrafish development and tail regeneration is a new and emerging field in biomedical research. The in vivo delivery and bioactivity of retinoic acid from single implanted colloidosomes in partially amputated caudal fins are shown at the phenotype and genotype level. The colloidosomes are biocompatible since no signs of inflammation are observed. With these initial studies, the use of colloidosomes as single implantable beads is demonstrated for the local in vivo release of bioactive drugs. It is envisioned that these single particles can be applied for a broad range of hydrophobic drugs.

Schottky junctions made from a titanium dioxide nanotube (TiO₂NT) array in contact with a monolayer graphene (MLG) film are fabricated and utilized for UV light detection. The TiO₂NT array is synthesized by the anodization and the MLG through a simple chemical vapor deposition process. Photoconductive analysis shows that the fabricated Schottky junction photodetector (PD) is sensitive to UV light illumination with good stability and reproducibility. The corresponding responsivity (R), photoconductive gain (G), and detectivity (D*) are calculated to be 15 A W⁻¹, 51, and 1.5 × 10¹² cm Hz^1/2 W⁻¹, respectively. It is observed that the fabricated PD exhibits spectral sensitivity and a simple power-law dependence on light intensity. Moreover, the height of the Schottky junction diode is derived to be 0.59 V by using a low temperature I–V measurement. Finally, the working mechanism of the TiO₂NT array/MLG film Schottky junction PD is elucidated.

Highly conductive biocompatible graphene is synthesized using ecofriendly reduction of graphene oxide (GO). Two strains of non-pathogenic extremophilic bacteria are used for reducing GO under both aerobic and anaerobic conditions. Degree of reduction and quality of bacterially reduced graphene oxide (BRGO) are monitored using UV–vis spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Structural morphology and variation in thickness are characterized using electron microscopy and atomic force microscopy, respectively. Electrical measurements by three-probe method reveal that the conductivity has increased by 10⁴–10⁵ fold from GO to BRGO. Biocompatibility assay using mouse fibroblast cell line shows that BRGO is non-cytotoxic and has a tendency to support as well as enhance the cell growth under laboratory conditions. Hereby, a cost effective, non-toxic bulk reduction of GO to biocompatible graphene for green electronics and bioscience application is achieved using halophilic extremophiles for the first time.

The presence of magnetic nanoparticles (NPs) in physiological systems induces toxicity through its effects on mitochondrial function and reactive oxygen species (ROS) imbalance. Magnetic NP induced cytotoxicity has been elaborately evaluated for impending threats, however, a detailed investigation is lacking. It is shown that the interaction of Fe₃O₄ NPs with cytochrome c can lead to different events based on the NPs to protein ratio, the solution conditions, and the type of surface protection. At low NPs concentration, rapid binding and subsequent electron transfer are the preferred events while at higher concentration slow oxidative modification of the protein is initiated. The slow event of protein modification yields conformational disorientation, loss of stability, and formation of amyloid-like structures with cytochrome c. The possibility that the NP induced oxidative stress and age can work in concert to compromise different aspects of cellular quality control processes is discussed. Suitable surface modifications of the NPs inhibit their direct binding to the protein molecules and minimize NP induced toxicity.

Solution-phase synthesis of colloidal nanoparticles with precisely tailored properties is one of the fastest growing research topic and represents the most critical foundation to implant nanotechnology in a variety of areas to boost performance of traditional systems. Comprehensive understanding of the nucleation and growth mechanisms involved in the formation of colloidal nanoparticles is very important to realize rational design and synthesis of well-tailored nanoparticles and requires appropriate in situ techniques to probe the kinetics of the synthetic reactions. Synchrotron hard X-rays represent a class of promising probes for solution-phase reactions due to their strong penetration in ambient environment and solutions. This review completely summarizes the in situ synchrotron X-ray techniques emerged in the recent years for real-time probing nanophase evolution of colloidal nanoparticles. Typical examples of colloidal nanoparticle syntheses are discussed in detail to shed the light on the advantages and disadvantages of individual techniques.

A facile approach to the synthesis of pressure and temperature dual-responsive polystyrene (PS) microbeads with controlled sizes via dispersion polymerization is described. Three different luminophors are selected and directly introduced into the reaction system and thus incorporated into the resultant PS microbeads during polymerization. By manipulating the reaction conditions, including concentrations of the initiator and monomer, polarity of the reaction medium, and injection rate for the monomer, uniform PS microbeads with sizes ranging from 1 to 5 μm are obtained. When a light source centered at 365 nm is used to excite all the luminophors in the PS beads, three distinct and resolvable emission peaks corresponding well with the luminophors are observed. By taking advantage of their sensitive responses to both pressure and temperature, the PS beads can be utilized for quantitative measurements of these two stimulations simultaneously. The PS beads loaded with multiple luminophors have the ability to serve as building blocks for the fabrication of novel sensing and imaging devices and therefore provide a promising strategy for the study of aerodynamics.

Hollow nanostructures are used for various applications including catalysis, sensing, and drug delivery. Methods based on the Kirkendall effect have been the most successful for obtaining hollow nanostructures of various multicomponent systems. The classical Kirkendall effect relies on the presence of a faster diffusing species in the core; the resultant imbalance in flux results in the formation of hollow structures. Here, an alternate non-Kirkendall mechanism that is operative for the formation of hollow single crystalline particles of intermetallic PtBi is demonstrated. The synthesis method involves sequential reduction of Pt and Bi salts in ethylene glycol under microwave irradiation. Detailed analysis of the reaction at various stages indicates that the formation of the intermetallic PtBi hollow nanoparticles occurs in steps. The mechanistic details are elucidated using control experiments. The use of microwave results in a very rapid synthesis of intermetallics PtBi that exhibits excellent electrocatalytic activity for formic acid oxidation reaction. The method presented can be extended to various multicomponent systems and is independent of the intrinsic diffusivities of the species involved.

Metal-free nitrogen and phosphorus dual-doped, electrocatlytically active, functionalized nanocarbon (FNC) and photoluminescent carbon nanodots (PCNDs) are simultaneously synthesized using a facile one-pot microwave-assisted process. The successful incorporation of phosphorus and nitrogen to oxygen rich PCNDs and FNC are confirmed using surface morphological and spectral studies. The characterization studies of FNC further reveals the presence of edge-plane-like sites/defects and remarkable electrocatalytical activity. In addition to the electroctalytical activity, FNC shows attractive properties as a metal-free oxygen reduction catalyst and is resistant to methanol crossover effects in alkaline media. The 5–10 nm PCNDs, which exhibit blue fluorescence under UV exposure, are successfully used for bioimaging applications.

Light-controlled electrical behavior of polymer/nanoparticle hybrid system in ambient condition is demonstrated. By embedding gold nanoparticles (Au NPs) in a poly(3-hexylthiophene) (P3HT) matrix, the photoresponses of the nanocomposite films are enhanced. The electrical behavior of the P3HT/Au NPs nanocomposite transistors and inverters are tuned over a wide range in depletion mode. UV-visible absorption spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and steady-state photoluminescence (PL) spectroscopy are used to analyze the nanocomposite films. The findings provide a better understanding of light-induced threshold voltage shifts of P3HT-based field-effect transistors and inverters and demonstrate their potential applications in electronic signal modulation for solution-processed integrated circuits.

A one pot synthesis of alumina supported faceted nickel nanoparticles is carried out following a simple, inexpensive, and sustainable pathway. Tailoring the different chemical steps of catalyst preparation allow the faceted morphology to be maintained while reducing the organic leftover. Moreover, this work shows the key role of the halide ions on the nanoparticles shaping that occurs during the reduction step under H₂. The predominant role of the {111} facets on the performance of the resulting supported nanocatalysts is also demonstrated. Indeed, catalytic tests in selective hydrogenation of polyunsaturated hydrocarbons performed for both faceted nanocatalysts and reference Ni show a clear selectivity enhancement for the former. The positive impact of {111} faceted Ni catalysts on hydrogenation selectivity is of particular interest to reduce the purification steps after the catalyzed reaction.

Small-sized monodisperse Pd-Ag alloy nanocrystals (NCs) are synthesized via a solid-liquid and solid-solid phase chemical route, i.e., sequential reduction of Pd(NO₃)₂ and AgNO₃ solid precursors in the liquid mixture of dodecylamine and 1-octadecene, followed by fusion of formed Pd and Ag NCs at 250 °C. By controlling the addition sequence and molar ratio of the metallic precursors, a series of Pd-Ag alloy NCs, including Pd₅Ag, Pd₂Ag, PdAg, PdAg₂, and PdAg₅, is obtained. The alloy NCs are highly crystallized and exhibit a strong atomic ensemble in addition to component-dependent electronic effects. Pd₂Ag NCs have unique structure and electronic properties, showing a much faster electron transfer process at a modified glassy carbon electrode interface compared with that of other alloys. Therefore, the Pd₂Ag NCs are chosen as the electrocatalyst to evaluate the performance of Pd-Ag nanoalloy and a novel non-enzymatic glucose biosensor is fabricated. The biosensor exhibits an acceptable reproducibility, a good stability and low interferences, which can be used to examine glucose in clinic blood serum samples. This work provides a simple multiphasic reaction system to synthesize binary alloy NCs with well-controlled componential ratio and opens the avenue to utilize them in biosensing or other advanced technological fields.

It is of scientific importance to obtain graphene quantum dots (GQDs) with narrow-size distribution in order to unveil their size-dependent structural and optical properties, thereby further to explore the energy band diagram of GQDs. Here, a soft-template microwave-assisted hydrothermal method to prepare GQDs with diameters less than 5 nm ± 0.55 nm is reported. The size-dependent photoluminescence (PL) quantum yield (QY) decay lifetime and electron energy loss spectroscopy (EELS) of the GQDs are studied systematically. The QY of the GQDs with an average diameter of 2 nm is the highest (15%) among all the samples investigated and the QY decreases with increasing diameter of the GQDs. The size-dependence of the PL decay lifetime is also observed. The result suggests that spatial confinement effects related to radiative relaxation play an important role in the size-dependent decay lifetime. A realistic energy band diagram of the GQDs is deduced from the experimental results.

The assembly, cellular internalization, and cytotoxicity of nanoparticles based on physical hydrogels of poly(vinyl alcohol) (PVA) are reported. PVA nanoparticles are assembled using a liposomal templating technique followed by removal of the lipids using isopropanol, a process that requires the presence of a custom-made block copolymer, poly(vinyl alcohol-b-vinyl pyrrolidone), to avoid aggregation of the nanoparticles. Polymer hydrogelation is induced via incubation in aqueous isopropyl alcohol solution, which results in PVA hydrogel nanoparticles (PVA HNP) with excellent colloidal stability and stability towards disintegration over at least 24 h. Pristine PVA HNP are found to be remarkably stealth-like and exhibit negligible cellular internalization. This feature is likely inherent with the low fouling nature of PVA and makes PVA HNP attractive for targeted drug delivery with a low level of association with non-targeted cells and tissues. Blending PVA with varied amounts of collagen results in colloidal hydrogel particles with a well pronounced tendency towards association with mammalian cells, specifically hepatocytes and endothelial cells. The association of PVA HNP elicits minimal changes in cellular proliferation, making these novel hydrogel particles convenient tools for drug delivery applications and creation of implantable artificial organelles and sensors.

Synergetic cooperation of individual components of the nanocomposites (NCs) is responsible for their novel properties that lead to various technological applications. A simple chemical process depicting the deposition of functionalized gold nanoparticles on the surface of boron nitride nanosheets (BNNSs) in solution is reported. The structure, chemical composition, and optical properties of nanosheets are systematically studied. The deposition of Au nanoparticles on BNNS (BNNS_Au) results in plasmonic band modulation, thus altering the optoelectronic properties of BNNSs. The intense surface plasmon absorption band of BNNS_Au is narrowed and red-shifted relative to the absorption band of as synthesized monometallic BNNSs. The observations reflect the strong interfacial interaction between BNNS and Au nanoparticles. This approach constitutes a basis for a simple process leading to the preparation of functionalized BNNSs and their utilization as nanoscale templates for assembly and integration with other nanoscale materials for futuristic optoelectronic devices.

The metallophilic bond is a weak interaction between closed-shell ions and has been widely used a probe for various sensing of toxic chemicals for environmental safety concerns. Here, the interaction between Au nanoclusters (NCs) and metallic ions (mercury (Hg²⁺) and copper (Cu²⁺) ions) is explored using steady-state and time-resolved luminescence and transient absorption measurements. For Hg²⁺ ions, the delayed fluorescence (DF) of bovine serum albumin (BSA) protected Au₂₅ (Au₂₅@BSA) NCs is quenched via an effective triplet state electron transfer through the metallophilic bond. However, the Cu²⁺ ions do not alter the DF in Au₂₅@BSA NCs because of the absence of the metallophilic interaction. Furthermore, for Au₈@BSA and Au₁₀@histidine, in which there are no Au⁺ ions on the surface, the fluorescence is not quenched by Hg²⁺ ions. Such a novel triplet electron transfer process through metallophilic bonds are observed and reported for the first time. The reduction of the reverse intersystem crossing is the crucial for Hg²⁺ ion sensing in the fluorescent Au₂₅@BSA NCs.

Biocompatible, near-infrared luminescent gold nanoclusters (AuNCs) are synthesized directly in water using poly(ethylene glycol)-dithiolane ligands terminating in either a carboxyl, amine, azide, or methoxy group. The ≈1.5 nm diameter AuNCs fluoresce at ≈820 nm with quantum yields that range from 4–8%, depending on the terminal functional group present, and display average luminescence lifetimes approaching 1.5 μs. The two-photon absorption (TPA) cross-section and two-photon excited fluorescence (TPEF) properties are also measured. Long-term testing shows the poly(ethylene glycol) stabilized AuNCs maintain colloidal stability in a variety of media ranging from saline to tissue culture growth medium along with tolerating storage of up to 2 years. DNA and dye-conjugation reactions confirm that the carboxyl, amine, and azide groups can be utilized on the AuNCs for carbodiimide, succinimidyl ester, and Cu^I-assisted cycloaddition chemistry, respectively. High signal-to-noise one- and two-photon cellular imaging is demonstrated. The AuNCs exhibit outstanding photophysical stability during continuous-extended imaging. Concomitant cellular viability testing shows that the AuNCs also elicit minimal cytotoxicity. Further biological applications for these luminescent nanoclustered materials are discussed.

A directional point-to-point growth of microwires of gold nanoparticles (AuNPs) self-organized on Aspergillus niger (A. niger) templates by utilizing positive phototropic fungal response to different spectral ranges of visible light is reported. A. niger serves as a living template for the self-organization of monosodium glutamate (MSG) capped gold colloids under controlled nutrient trigger and appropriate light, temperature, and humidity conditions. The experimental results show that control of these parameters eliminates the need for any microchannels for the directional growth of microwires. The growth rate of fungal hyphae increases exponentially under light illumination compared to its growth in the dark under similar conditions. White light is found to be most suitable to trigger the directional growth. Gold microwires of about 1 to 2 μm diameter and length exceeding 1 mm are grown within a week with a maximum divergence of 40–50° from the light path regardless of the wavelength of the light irradiation. Phototropic response of fungi has been investigated intensively over the last three decades, but this is the first report on the collective use of microbial tropism and directed biomimetic self-organization of metallic nanoparticles on living organisms.

Bioprobes based on fluorescent ruby nanoparticles, which are suitable for ultrasensitive imaging, are reported. A stable aqueous/buffer colloid, permitting facile conjugation to proteins, is produced by femtosecond laser ablation of ruby and the nanoparticles (mean size 17 nm) are photostable, with long lifetime (1–4 ms) 694 nm emission. With time-gating complete (>20 dB) suppression of cell autofluorescence and suppression of exogenous fluorophores is observed. Nanoparticles are imaged in as-grown cells and those immunolabeled with quantum dots. Immunoassay binding to target biomolecules is also demonstrated.

Existing methods for preparing complex particles, i.e., hollow porous, depend on either multiple steps or a complex reactor design. Here, a straightforward method to prepare unique polymer particles with complex shapes via the use of simple equipment and readily available chemicals is reported. Beads, capsules, and rods with uniform size and interconnected pores are obtained through the formation of high internal phase emulsion (HIPE) droplets in a microfluidic channel. The method is applicable to a broad range of (meth)acralates. Controlling physical properties, such as viscosity and emulsion stability, is key to control the shape of the resulting particles. Post-modification of the particles via click chemistry, their application in liquid marble formation, and their use as droplet reactors are also demonstrated.

A new kind of silicon nanowire (SiNWs)-based nanoelectrode assembly, a gold-nanoparticle-decorated silicon nanowire array (AuNPs@SiNWsAr), is employed for the construction of high-performance electrochemical sensors. Significantly, the electrochemical nanosensors are capable of sensitive detection of various electroactive molecules (e.g., dopamine (DA), ascorbic acid (AA), hydrogen peroxide (H₂O₂), and glucose). Further, DA molecules loaded on the surface of AuNPs@SiNWsAr preserve stable high electroactivity overnight without special protection, while free DA molecules may lose their biological activity due to severe oxidization in ambient environment. These findings may offer new opportunities for the design of high-performance electrochemical nanosensors with high sensitivity and robust stability.

Fluorinated Eu-doped SnO₂ nanostructures with tunable morphology (shuttle-like and ring-like) are prepared by a hydrothermal method, using NaF as the morphology controlling agent. X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy are used to characterize their phase, shape, lattice structure, composition, and element distribution. The data suggest that Eu³⁺ ions are uniformly embedded into SnO₂ nanocrystallites either through substitution of Sn⁴⁺ ions or through formation of Eu-F bonds, allowing for high-level Eu³⁺ doping. Photoluminescence features such as transition intensity ratios and Stark splitting indicate diverse localization of Eu³⁺ ions in the SnO₂ nanoparticles, either in the crystalline lattice or in the grain boundaries. Due to formation of Eu-F and Sn-F bonds, the fluorinated surface of SnO₂ nanocrystallites efficiently inhibits the hydroxyl quenching effect, which accounts for their improved photoluminescence intensity.

With incorporation of gold nanoparticles, i.e., nanorods (AuNR) and nanospheres (AuNS), into a polyurethane-based shape-memory polymer (SMP) EG-72D matrix, SMP nanocomposite films capable of being remotely triggered by low-power laser are fabricated and characterized using UV-vis-NIR spectroscopy, X-ray scattering, and dynamic mechanical analysis (DMA). It is demonstrated that, with incorporation of very low concentration of gold nanorods (≈0.1 wt%), the mechanically programmed EG-72D/AuNR nanocomposite presents rapid response to low power laser irradiation (785 nm, ≈10 mW). Comparative studies on the laser irradiation response of EG-72D/AuNS and EG-72D/AuNR nanocomposite films suggest that AuNRs have significantly higher photothermal conversion efficiency than AuNS and on-resonance laser irradiation, matching the wavelength of the incident laser with the longitudinal plasmon resonance of AuNR, is necessary to induce the fast response of gold nanoparticle enabled SMP nanocomposites.

The energy gap between valence and conduction levels in colloidal semiconductor quantum dots can be tuned via the nanoparticle diameter when this is comparable to or less than the Bohr radius. In materials such as cadmium mercury telluride, which readily forms a single phase ternary alloy, this quantum confinement tuning can also be augmented by compositional tuning, which brings a further degree of freedom in the bandgap engineering. Here it is shown that compositional control of 2.3 nm diameter Cd_xHg_(1−x)Te nanocrystals by exchange of Hg²⁺ in place of Cd²⁺ ions can be used to tune their optical properties across a technologically useful range, from 500 nm to almost 1200 nm. Data on composition-dependent changes in the optical properties are provided, including bandgap, extinction coefficient, emission energy and spectral shape, Stokes shift, quantum efficiency, and radiative lifetimes as the exchange process occurs, which are highly relevant for those seeking to use these technologically important QD materials.

B-precursor acute lymphoblastic leukemia (B-ALL) lymphoblast (blast) internalization of anti-cytokine receptor-like factor 2 (CRLF2) antibody-armored biodegradable nanoparticles (AbBNPs) are investigated. First, AbBNPsaere synthesized by adsorbing anti-CRLF2 antibodies to poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles of various sizes and antibody surface density (Ab/BNP) ratios. Second, AbBNPs are incubated with CRLF2-overexpressing (CRLF2+) or control blasts. Third, internalization of AbBNPs by blasts is evaluated by multicolor flow cytometry as a function of receptor expression, AbBNP size, and Ab/BNP ratio. Results from these experiments are confirmed by electron microscopy, fluorescence microscopy, and Western blotting. The optimal size and Ab/BNP for internalization of AbBNPs by CRLF2+ blasts is 50 nm with 10 Ab/BNP and 100 nm with 25 Ab/BNP. These studies show that internalization of AbBNPs in childhood B-ALL blasts is AbBNP size- and Ab/BNP ratio-dependent. All AbBNP combinations are non-cytotoxic. It is also shown that CD47 is very slightly up-regulated by blasts exposed to AbBNPs. CD47 is “the marker of self” overexpressed by blasts to escape phagocytosis, or “cellular devouring”, by beneficial macrophages. The results indicate that precise engineering of AbBNPs by size and Ab/BNP ratio may improve the internalization and selectivity of future biodegradable nanoparticles for the treatment of leukemia patients, including drug-resistant minority children and Down's syndrome patients with CRLF2+B-ALL.

Although progress in the use carbon nanotubes in medicine has been most encouraging for therapeutic and diagnostic applications, any translational success must involve overcoming the toxicological and surface functionalization challenges inherent in the use of such nanotubes. Ideally, a carbon-nanotube-based drug delivery system would exhibit low toxicity, sustained drug release, and persist in circulation without aggregation. Here, carbon nanotubes (CNTs) coated with a biocompatible block-co-polymer composed of poly(lactide)-poly(ethylene glycol) (PLA-PEG) are reported to reduce short-term and long-term toxicity, sustain drug release of paclitaxel (PTX), and prevent aggregation. The copolymer coating on the surface of CNTs significantly reduces in vitro toxicity. Moreover, the coating reduces the in vitro inflammatory response. Compared to non-coated CNTs, in vivo studies show no long-term inflammatory response with CNT coated with PLA-PEG (CLP) and the surface coating significantly decreases acute toxicity by doubling the maximum tolerated dose in mice. In vivo biodistribution and histology studies suggest a lower degree of aggregation in tissues.

Zinc oxide nanoparticles (ZnO NPs) induce morphological transformation of Escherichia coli from its native rod-shape of ≈2–4 μm to filamentous cells of 20–40 μm in length. The transient response can only be observed at up to 3.5 h proliferation, beyond which the cytotoxic effect is neutralized and the rod-shape is restored. The filamentation is part of the bacterium SOS response to the Trojan horse-type internalization of undissolved ZnO solids. In the absence of ZnO solids, no cell filamentation can be observed from the leached soluble zinc fraction or dissolved zinc salt.

Eight fluorinated nanoparticles (NPs) are synthesized, loaded with doxorubicin (DOX), and evaluated as theranostic delivery platforms to breast cancer cells. The multifunctional NPs are formed by self-assembly of either linear or star-shaped amphiphilic block copolymers, with fluorinated segments incorporated in the hydrophilic corona of the carrier. The sizes of the NPs confirm that small circular NPs are formed. The release kinetics data of the particles reveals clear hydrophobic core dependence, with longer sustained release from particles with larger hydrophobic cores, suggesting that the DOX release from these carriers can be tailored. Viability assays and flow cytometry evaluation of the ratios of apoptosis/necrosis indicate that the materials are non-toxic to breast cancer cells before DOX loading; however, they are very efficient, similar to free DOX, at killing cancer cells after drug encapsulation. Both flow cytometry and confocal microscopy confirm the cellular uptake of NPs and DOX-NPs into breast cancer cells, and in vitro ¹⁹F-MRI measurement shows that the fluorinated NPs have strong imaging signals, qualifying them as a potential in vivo contrast agent for ¹⁹F-MRI.