Small

The cover illustrates how the “Trojan Horses” known as exosomes are the conveyors in the signaling transduction of nanoparticle-induced systemic immune activation. With the accelerating development and use of nanomaterials in industry and commercial products, the potential risks of manufactured nanoparticles to human health has become concerning. Here, respiratory exposure to manufactured magnetic iron oxide nanoparticles is shown to generate a significant number of exosomes in the lungs of mice. Exosomes are extracellularly secreted membrane vesicles for materials transportation and intercellular communication. In this case, these nanoparticle-induced exosomes are quickly eliminated from the alveolar region, transferring immune activation signals to the immune system. In those individuals who already have pre-existing allergic conditions (known as sensitized individuals), the exosomes can result in a delayed type of hypersensitivity reaction and promote severe allergic responses, whereas in unsensitized individuals, the resulting immune activation response is much lower. For more information, please read the Full Paper “Exosomes as Extrapulmonary Signaling Conveyors for Nanoparticle-Induced Systemic Immune Activation” by G. Nie, Y. Zhao, and co-workers, beginning on page 404.

The cover image shows how the shape of micro- and nanodroplets can be controlled by patterning surfaces with special hydrophilic regions surrounded by hydrophobic boundaries. Shaped droplets may be used as a simple tool to controllably pattern planar surfaces with microparticles and cells. Under spiral droplets, a gradient deposition pattern is observed. Shaped droplets of prepolymer solution may also be crosslinked to synthesize microgels with tailored 3D geometry. Finite element simulations provide a design platform by linking the shape of the hydrophilic regions to that of the droplets, microgels, and particle deposition patterns. For more information, please read the Full Paper “Designer Hydrophilic Regions Regulate Droplet Shape for Controlled Surface Patterning and 3D Microgel Synthesis” by A. Khademhosseini and co-workers, beginning on page 393.

Linear alkane polymerization is achieved on the Au(110) surface with 1D constrained nanochannels, which play a key role in the selective C–H activation and C–C bond coupling.

The cellular environment plays a significant role in cell phenotype and function. As such, physical properties of cell culture substrates including topography, roughness, and elasticity may be utilized to investigate the influence of these physical cues on the cellular response. In this review, strategies for modulating the physical properties of surfaces, the influence of these changes on cell responses, and the promise and limitations of these surfaces in in-vitro settings are highlighted, with a particular emphasis on elastic substrates.

The image shows an integrated graphene voltage amplifier, which paves the way for all-graphene analogue electronics. Signal amplification is obtained by fabricating graphene transistors in which the top gate overlaps with the source and drain contacts. This results in full-channel gating and therefore high transconductance at room temperature. The fabricated complementary amplifier has a voltage gain of 3.7 (11.4 dB) at 10 kHz, a total harmonic distortion in the audio frequency range of <1%, a unity-gain frequency of 360 kHz, and a −3 dB bandwidth of 70 kHz. The obtained values demonstrate that, among other applications, the present graphene amplifier is suitable for high-fidelity amplification of audio signals.

A graphene audio voltage amplifier is fabricated by overlapping the gate with source/drain contacts. The fabricated complementary amplifier has a voltage gain of 3.7 (11.4 dB) at 10 kHz, a total harmonic distortion in the audio frequency range of <1%, a unity-gain frequency of 360 kHz, and a −3 dB bandwidth of 70 kHz.

Linear, 2-arm branched, and 4-arm starlike peptides are designed and their antimicrobial and hemolytic activities are characterized. Branching molecular designs are demonstrated to enhance antimicrobial activity and reduce undesired hemolysis, leading to better selectivity towards microbes over mammalian cells. This unique strategy can also be applied to optimize the molecular structures of other types of macromolecular antimicrobials such as polymers.

Polymeric nanoparticles are promising for gene therapy and stem cell reprogramming using nonviral vectors. A novel assay utilizing nanoparticle tracking analysis is developed to easily quantify the number of plasmids within polymeric nanoparticles while in aqueous solution. Particles effective at co-transfecting primary human fibroblasts are approximately 100 nm in diameter and contain around 100 plasmids per particle.

Cu²⁺-modified DNA nanostructures are investigated using differently sized DNA rings that are composed of core and extension motifs. Chemical reduction and current measurements are adopted for verifying Cu²⁺ modification, and the results provide clear evidence for the co-ordination of Cu²⁺ in DNA structures.

A reversible preconcentration of gold nanoparticles (AuNPs) can be used for chemical analysis based on surface-enhanced Raman scattering in a microfluidic system. AuNPs homogeneously dispersed in solution are locally preconcentrated by charge-selective ion extraction through a pair of negatively charged polyelectrolyte plugs. This phenomenon creates dynamic hot spots among the preconcentrated AuNPs, which can also be redispersed as required.

The image features a new apparatus that combines a scanning-probe microscope and a solid-state nanopore device. The pore and probe are immersed in an ionic solution where an applied bias voltage creates a current through the pore. The pore is occluded as the probe approaches it, allowing the determination of the 3D access resistance change map outside the nanopore. The device was developed for application in nanopore-based single-molecule DNA sequencing.

A novel apparatus that integrates solid-state nanopore ionic current measurement with a scanning probe microscope is constructed and used to characterize the access resistance of solid-state nanopores. The apparatus is capable of recording the current blockage 3D map caused by the probe tip I_s(x,y,z) in salt solution. Access resistance is an important parameter for understanding the nanopore translocation process of single DNA and protein molecules.<?br?>

Droplets conform to hydrophilic regions with hydrophobic boundaries at the macroscale and microscale. Shaped droplets of prepolymer solution become shaped microgels once crosslinked. Sedimenting microparticles contained in a microdroplet form a gradient deposition pattern. Finite element simulations provide a computational design platform for shaped droplets and corresponding surface patterning and microgels.

Nanoparticle (NP)-induced exosomes are conveyors in the signaling induction of systemic immunostimulation. Respiratory exposure of magnetic iron oxide nanoparticles (MIONs) can induce exosome secretion from antigen-presenting cells (APCs, probably alveolar macrophages) in the alveolar region. These exosomes sequentially fast transfer to an extrapulmonary site, and extrapulmonary-transferred exosomes are capable of remarkable activation of systemic T cells.

Biolistic-mediated delivery of mesoporous silica nanoparticles (MSNs) and DNA to plant cells is performed via two strategies: gold plating the surfaces of MSNs to increase momentum during bombardment, and co-bombardment of the MSNs with 0.6 μm gold particles. In both cases, a CaCl₂/spermidine-based protocol is used to coat DNA onto the particles.

Highly wrinkled graphene oxide membranes are formed at the water–air interface by a cross-linking reaction. The corrugation of the membrane can be controlled by the temperature and concentration of the cross-linking species. The corrugated graphene oxide membrane is a good scaffold for the growth of human mesenchymal stem cells and promotes spontaneous stem-cell differentiation into oesteoblast lineage. The corrugated film structure reduces face-to-face stacking of the graphene and good capacitance values (211 F g⁻¹) can be obtained when the film is used in supercapacitors.

Fabrication of sufficiently thick mesoporous TiO₂ photoelectrodes with morphology control on the 10 nm length scale is essential for solid-state dye-sensitized solar cells (ss-DSC). This study of the temporal evolution of block-copolymer-directed mesoporous TiO₂ films during annealing and calcination enables the build-up of sufficiently thick films for high-performance ssDSC devices.

A polysaccharide of mulberry leaves (MPS) is isolated from mulberry leaves and cationized by grafting ethylenediamine onto the MPS backbone to obtain the cationic polysaccharide of mulberry leaves (CMPS). The plasmid DNA/CMPS nanoparticles are prepared by combining plasmid DNA with CMPS and used to transfect mesenchymal stem cells, which results in significantly higher transfection efficiency than when Lipofectamine 2000 is used.

Flexible graphene paper infiltrated by carbon black (CB) nanoparticles using a vacuum filtration method is developed as a high-performance electrode material for supercapacitors. The self-restacking of graphene sheets is mitigated by the introduction of carbon black as a spacer. The pillared graphene paper-based supercapacitors exhibit excellent electrochemical performance and cyclic stability compared with undoped graphene paper.

Fuel-free nanomotors are essential for future in-vivo biomedical applications. The first example of towing drug-loaded magnetic polymeric particles using magnetically driven fuel free flexible nanomotors is described. The effect of the cargo size upon the swimming performance is evaluated experimentally and compared to a theoretical model. Potential applications of these cargo-towing motors are demonstrated by using the directed delivery of drug-loaded microparticles to HeLa cancer cells in biological media.

2 nm Pt nanoparticles (NPs) are impregnated in mesoporous silica substrates (SBA-15). A change in the Fourier transformation indicates the deformation of the Pt NPs in contact with the SBA-15 surface, from spherical to flat morphology.