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The cover picture shows neurites emanating from a dorsal root ganglia that was seeded in a microwell on a nanofiber-based membrane. The simple and versatile fabrication method of the membrane, which features arrayed microwells and 1D structural cues on its surface, involves electrospinning with an array of stainless steel beads as the collector. The diameter and depth of the microwells and the distance between adjacent microwells can all be separately adjusted by varying the size, separation, and arrangement of the steel beads. Using this novel class of nanofiber-based substrates, neuronal networks and cell microarrays can be formed. The unique architecture of these electrospun nanofiber membranes may also be useful for a range of other biomedical applications. For more information, please read the Communication “Nanofiber Membranes with Controllable Microwells and Structural Cues and Their Use in Forming Cell Microarrays and Neuronal Networks” by Y. Xia and co-workers beginning on page 293.

The cover picture shows supramolecular ordered structures, which are achieved through the self-assembly of small rigid molecules. The self-association of phenylpyrimidine-based dimeric species through directional H-bonding between two lateral pyridin-2(1H)-one units of neighboring molecules allowed the formation of highly compact 1D supramolecular polymers by self-assembly on graphite. The concentration-dependent study by scanning tunneling microscopy at the solid-liquid interface is corroborated by dispersion-corrected density functional studies and revealed the controlled generation of either linear supramolecular 2D arrays or long helical supramolecular polymers with a high shape persistence. For more information, please read the Full Paper “Rigid Dimers Formed through Strong Interdigitated H-Bonds Yield Compact 1D Supramolecular Helical Polymers” by F. Hanke, J.-M. Lehn, P. Samorì, and co-workers, beginning on page 342.

Neural scaffolds: A method for fabricating electrospun nanofiber membranes with arrayed microwells and aligned structural cues on their surfaces by using a collector assembled from stainless steel beads is reported. It is demonstrated that formation of cell microarrays and neuronal networks can be achieved using this novel class of nanofiber scaffolds.

A C₆₀-capped poly(3-hexylthiophene) dyad molecule (PCB–P3HT) serves as a “surfactant” to enhance the solubility of fullerenes in poor solvents such as tetrahydrofuran, a selective good solvent for P3HT. Moreover, the phase separation of PCB–P3HT in thin films leads to well-defined nanostructures wherein the solvent plays a vital role in determining the morphology and the structure of these self-assembling structures.

High quality cellulose nanocrystals are synthesized using a simple one-step procedure with ammonium persulfate. This versatile method processes a variety of cellulosic biomass without the need for pretreatments to remove non- cellulosic plant contents.

Highly selective DNA probes prepared by functionalizing gold nanoparticles with nonionic morpholino oligos are described. The nanoparticle probes offer enzyme-like selectivity based simply on hybridization reactions, allowing visual detection of a perfectly matched target within a large excess (>1000-fold) of single-base-mismatched DNA.

Photoinduced hydrogen nanogenerators are prepared by closely integrating sensitizer and catalyst in a nanogel network. The nanogenerators operate an internal electronic transmission circuit by coordinating the internal sensitizer and catalyst. This nanomaterial could be useful as an artificial photosynthetic system for solar-energy conversion.

A label-free immunoassay based on a simple, surface-enhanced Raman scattering (SERS) approach is reported. Biotin-conjugated antibodies are at­­tached to avidin-aggregated Ag nanoparticles via biotin–avidin biorecognition. More highly sensitive protein detection and more biocompatible protein adsorption are achieved compared to previous relevant methods. Importantly, a SERS intensity ratio of two bands is found to be sensitive to the concentration of corresponding antigens.

A novel, fast, and low-cost method for fabricating large-area arrays of organic-material-based filamentary nanostructures is presented. The technique, auxiliary solvent-based sublimation-aided nanostructuring (ASB-SANS), only takes minutes and exploits a templating matrix easily removable by sublimation. Proof-of-concept patterns fabricated out of poly(methylmethacrylate) (PMMA) and carbon nanotubes (CNTs) are demonstrated.

A simple and generalized synthetic approach is developed for creating mesoporous shells on zeolite crystals. This method allows for the tailoring of thickness, pore size, and composition of the mesoporous shell, and can be applied to zeolites of various structures, compositions, and crystal sizes.

Optical imaging approaches are used to characterize the interactions of CdSe quantum dots (QDs) with live immune cells in order to gain insight into particle shape and size-dependent behavior. Through the use of total internal reflectance fluorescence (TIRF) and hyper-spectral confocal microscopy (HCM), Timlin and co-workers are able to characterize particle diffusion and partitioning within the plasma membrane, cellular uptake kinetics, as well as sorting of particles into lysosomes. TIRF imaging reveals that rod-shaped QDs are internalized into the cell two- to three times more slowly than more spherical ones, and HCM suggests that QDs tend to partition within the cell membrane into regions containing a single particle type. on page 333

Using hyperspectral confocal fluorescence (HCF) microscopy, it is shown that quantum dots of various sizes and shapes partition themselves into distinct regions within the cell membrane of RBL-2H3 rat mast cells. HCF microscopy allows for deconvolving the signal from multiple, overlapping fluorophores in the sample in order to reveal precise concentrations and distributions of nanoparticles in the cell.

Hydrogen-bonded supramolecular polymers are observed by scanning tunneling microscopy at the solid–liquid interface. The architecture consists of rigid molecular modules self-assembled via multiple H-bonding into a compact supramolecular polymer. A controlled geometry of the virtually infinite 1D architecture, i.e., a linear or helical motif, is obtained by working at different concentrations.

Ion-sensitive polyelectrolyte capsules for protons, sodium, potassium, and chloride ions were fabricated by embedding sensor dye molecules, whose fluorescence intensity depends on the ion concentration, and reference dye molecules into their cavities. The fluorescence response of every sensor type to changes in ion concentration was quantitatively evaluated by ratiometric fluorescence spectroscopy and ratiometric fluorescence microscopy measurements.

A layering approach to deliver small interfering RNA (siRNA) with an extended gene-silencing effect is developed. Multilayers of siRNA are fabricated on a nanometer-sized core with a protease-sensitive polypeptide, which can be degraded gradually by intracellular protease, resulting in a prolonged siRNA effect.

Local electric fields can be tuned dramatically by varying the diameter of quasi-3D gold plasmonic nano­structure arrays, as indicated by 3D finite-difference time-domain calculations. Utilizing quasi-3D arrays that exhibit a maximum electric field intensity either at the bottom (gold nanodisks) or on the top (gold film patterned with nanoholes), the optimal surface-enhanced Raman scattering sensitivity for the detection of small molecules or large microorganisms can be achieved.

The rapid reduction of MoO₂Cl₂ precursor triggers the nucleation of 2 nm MoO₂ nanospheres with a hexagonal crystal structure. An increase in particle size induces a crystal phase transition from hexagonal to monoclinic. The transformation from spheres into rods emerges as a complex process driven by oriented attachment.

A strategy to manipulate cell operations is based on the membrane-receptor-specific interactions between colloidal peptide-capped gold nanoparticles (NPs) and human umbilical vein endothelial cells. The specific binding of the peptide-capped particles to angiogenic receptors is demonstrated. The cellular fate of the functional NPs is imaged and the influence of the peptide-coated NPs on the gene expression profile of hypoxic and angiogenic genes is monitored.

A highly sensitive labeling method that translates antigen–antibody recognition processes into DNA-detection events that can be greatly amplified via isothermal rolling circle amplification (RCA) is applied. Using this method, it is demonstrated that the identification of specific protein markers can be achieved on tumor-cell surfaces in miniaturized nanoliter reaction droplets.

The anticancer drug doxorubicin (DOX) can be released in a controlled manner from degradable and dendritic amphiphiles by changing the light irradiation time. Different sugar- and light-sensitive groups (e.g., diazonaphthoquinone, DNQ) are modularly conjugated in the nanocarriers. The sugar-coated micelles demonstrate specific binding with lectins, which makes them useful for targeted drug-delivery vesicles.

Phase-pure α-Fe₂O₃ nanoarchitectures with both a mesoporous morphology and crystalline domain structure can be readily produced in the form of thin films through coassembly of hydrated ferric nitrate with a poly(ethylene-co-butylene)-block-poly(ethylene oxide) diblock copolymer. These novel materials exhibit enhanced lithium-ion storage capabilities and excellent cycling stabilities by suppressing the irreversible phase transformations that are observed in microcrystalline α-Fe₂O₃.