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The cover picture shows Ga nanoclusters in a well-ordered, self-assembled array on the Si(111) − 7 × 7 surface. Ultrahigh vacuum scanning tunneling microscopy was used to simultaneously image the topography and the local density of states (LDOS) of this system. The image is a 10 nm × 10 nm region with the LDOS plotted as a color map over the topography. The results indicate that the electronic charge on the surface has redistributed due to the presence of the Ga nanocluster array and that the nanoclusters are connected in a two-dimensional network of higher differential tunneling conductance. For more information, please read the Communication “Atomically Resolved Charge Redistribution for Ga Nanocluster Arrays on the Si(111)-7 × 7 Surface” by M. Hersam et al, beginning on page 915.

Growth and structural analysis of epitaxial InAs/InSb nanowire heterostructures are demonstrated for the first time. InSb segments are found to be perfect crystals, free of stacking faults or other major defects, and have a sharp interface with InAs (see image). After growth the seed particle is a single crystal nearly lattice matched to the nanowire. InSb segments are n-type and form ohmic contacts with Ni/Au electrodes.

In stable condition: Highly luminescent and stable CdSe clusters show optical properties similar to those of molecules rather than nanocrystals (e.g., the photoluminescence (PL) lifetime, see picture). The synthesis of (CdSe)_33,34 clusters is thermodynamically preferred. These “magic-sized” clusters could be used as uniform building blocks for optoelectronic nanodevices.

Staying single: Individual, ultralong, single-crystalline Te nanotubes become unintentionally doped when synthesized by a chemical method. They show metallic character in the wide temperature rangeof 5–300 K (see graph), which issupported by first-principles density functional theory calculations. Nanodevicesare fabricated based on a single Tenanotube by using a focused-ion-beamdeposition technique.

Water-soluble fluorescent core/shell nanoparticles containing multiple -COOH groups are synthesized via atom-transfer radical polymerization by applying perylenediimide derivatives as the template. This novel dye combines good water-solubility and attractive optical properties. It specifically stains the cell nucleus by binding to positively charged nuclear proteins (see image).

GaAs nanowires are synthesized by molecular-beam epitaxy (MBE) without using gold as a nucleation seed. The synthesis can be tuned from 1D to 2D by changing the MBE growth conditions. This allows the deposition of quasi 1D quantum wells on the nanometer-wide facets of the nanowires, resulting in a prismatic geometry (see image).

A model to predict the density of metallic nanostructures (see image) during an electrochemical deposition process is presented. The quantitative consideration of pH gradient inside high-aspect-ratio nanostructures coupled with a kinetic model allows a quantitative prediction of the structure morphology depending on nanoelectrode geometry and growth parameters and of the morphology evolution with deposition time.

Fluorescent thermometry presents a cheap and efficient alternative for small-scale thermal characterization. The use of dried Rhodamine B (see image) as a probe for surface-temperature mapping is demonstrated. The approach is applied in the evaluation of the temperature distribution along resistively heated micro- and nanowires. The temperature is found to be highly uniform along metal wires on silicon.

Self-assembled Ga nanoclusters form a well-ordered array on the Si(111)-7 × 7 surface. Scanning tunneling microscopy and spectroscopy map the electronic structure of these arrays at the atomic scale. In the image, the local density of states is plotted as a color map over the topography and shows a continuous 2D network of increased differential tunneling conductance connecting the nanoclusters.

One material for two purposes: Poly(ethylene glycol) is used as a novel etch resist to generate both raised and recessed nanoscale solid-state structures (see image). This novel resist is inexpensive, easy to use, and affords sub-100-nm resolution.

Building nanobridges: Direct integration of an ensemble of GaN nanowires (n) onto a microchip produces a viable nanobridge (NB) device with good alignment and contact performance, the design of which demonstrates the potential of nanowires for sensor development. These GaN NBs have strong surface-enhanced photoconductivity with ultrahigh responsivity (see graph).

Electrospinning is presented as a technique for the debundling and isolation of carbon nanotubes. Nanotubes are electrospun with polyvinyl alcohol to produce composite nanofibers. Using a Raman spectroscopic technique, with a number of lasers of different excitation energies, the nanotubes are brought into resonance. Individual tubes (see image) can be identified from the presence of characteristic radial-breathing modes.

A new class of silica fluorescent nanoparticles (≈30-nm diameter; see image) is described, in which organic fluorescent dyes are physically entrapped inside self-sealed silica nanochannels. The 1D confinement of the dye molecules inside the channels means the dyes can be packed without quenching fluorescence, ≈250 times denser inside the nanoparticles than in aqueous medium. The synthesized particles are compatible with labeling biological cells.

Stealth nanotubes: The stealth character of covalently PEGylated single-walled nanotubes (SWNTs, indicated by arrows in image) in vivo is studied. The nanotubes exhibit much longer blood-circulation half-life in vivo than the previous record for nanotubes and also a low hepatic uptake, vital to uses in drug-delivery systems. The benefits are reflected in the observed high tumor uptake of PEGylated SWNTs.

Single-layered titanium sulfide nanodisks (see image) are prepared for the first time using the wet chemical method. The size of the nanodisks are controlled by changing the experimental conditions. The synthesized nanodisks show interesting structural changes at room temperature.

Special branch: Branched nanocrystals of CdS (tripods and tetrapods; see image) are obtained with a simple solvothermal process through inclusion of dopant Se or Te. This causes CdS to nucleate in the zinc blende phase instead of the typical wurtzite phase, from which the subsequent 1D growth of wurtzite arms leads to the formation of the branched structures.

TERMinal filaments: Design of repeatable protein nanostructures is a limiting factor in the use of proteins as advanced materials templates. A capping protein of a new protein filament, γ PFD (see image), and a thermophilic extension resistant mutant (TERM) are constructed, control of overall length is demonstrated, and length distributions are quantitatively predicted.

Switched on: The electron-transport characteristics in multiporphyrinic systems are systematically analyzed. The aromaticity and π-conjugated framework control the electron-transport characteristics (see picture: tet = tetrameric porphyrin isomer). The π-conjugated framework of the monomer provides the ability to switch a single molecule between “on” and “off” states.

In situ lipopeptide synthesis on solid-supported lipid membranes (see image) is introduced and the ability to serve as receptor structures is evaluated. The interaction of functionalized vesicles is found to occur exclusively on peptides displaying maleimide-functionalized lipid bilayers.

Micro- and macropatterns of ordered mesostructured silica are fabricated on arbitrary flat and curved surfaces (see image) using a facile robot-directed aerosol-printing process. The aerosol droplets containing silica, surfactant, and solvent are deposited on a substrate in a fluid stage, allowing coalescence into a continuous phase. The surfactant molecules can be removed by photocalcination of the silica–surfactant nanocomposites.

Organic–inorganic nanocomposites: Both low-dimensional bar-coded metal oxide layers, which exhibit molecular hinging, and free-standing ordered organic nanostructures can be obtained from unique nanofibers of vanadium oxide (see figure). Bar-coded nanofibers comprise alternating segments of organic–inorganic (thiols–VO_x) material and are amenable to selective nanoparticle uptake.

The inside story: Surface-modified gold nanorods are intravenously injected into a mouse and their distribution is observed by near-IR light (see image). Surface plasmon (SP) bands of the gold nanorods are directly monitored in the mouse abdomen by near-IR spectroscopy. Changes of the SP bands indicate the distribution and aggregation of the gold nanorods in vivo.

That's a wrap! Polymer-wrapped self-assembled peptide nanotubes (see image), which resemble core/shell nanorods, show a remarkable dependency of the nanoscale structure on the mass of grafted synthetic polymers, which is found to be independent of the chemistry of the attached macromolecule.