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The cover picture shows mesoscopic crystals of hexa-benzo-coronene molecules obtained by temperature-enhanced solvent vapor annealing (TESVA) processing. By attaining a control over the hydrodynamic forces, TESVA allows for the self-assembly of small aromatic molecules into large, ordered crystals featuring an edge-on columnar type of arrangement, which differs from the morphologies obtained using conventional solution-processing methods such as spin-coating or drop-casting. This promotes reorganization from the scale of a few nanometers up to several hundreds of micrometers, leading to the formation of crystalline functional architectures. Novel C3 symmetric hexa-peri-hexabenzocoronenes functionalized with alternating hydrophilic and hydrophobic side chains (shown in red and blue, respectively, in the image) are used as model systems. For more information, please read the Full Paper “Temperature-Enhanced Solvent Vapor Annealing of a C3 Symmetric Hexa-peri-Hexabenzocoronene: Controlling the Self-Assembly from Nano-to Macroscale” by V. Palermo, K. Müllen, P. Samorí, et al. beginning on page 112.

The inside cover image shows lizards (10-µm line thickness) etched into a potassium haxacyanoferrate crystal (red) using a reaction-diffusion process initiated from a hydrogel stamp. The technique allows for direct printing of complex microarchitectures into a variety of materials with submicrometer resolution. These images are inspired by M. C. Escher's famous drawings and lithographs. For more information, please read the Concept by K. J. M. Bishop and B. A. Grzybowski, beginning on page 22.

The 2008 Trends in NanoTechnology conference was recently held in Oviedo, Spain. An overview of the conference highlights and speakers is presented.

Wet stamps pattern hard materials. Micropatterned hydrogel stamps soaked in chemical etchants can imprint various types of micro- and nanoarchitectures into metals, conductive oxides, semiconductors, glasses, and crystals. The method is well suited for the rapid prototyping of small-scale devices including multilevel microfluidic systems and curvilinear optical elements. The image shows disjoint Au plates formed by etching through Au foil (scale bar = 50 µm).

Dip-pen nanolithography is a highly versatile tool for the formation of metallic, semiconductor, or metal oxide nano structures on surfaces. Direct deposition of particles (see image), formation of anchoring sites or seeds, as well as formation of etch-resistant layers, allow for the highly controlled fabrication of 3D structures with precision in the nano meter range.

A new class of infinite co-ordination polymer microparticles showing highly selective adsorption of H₂ over N₂ is developed from the co-ordination chemistry of acid-functionalized Tröger's-base-derived ligands and Zn(II) metal ions.

Killer eggs! The temperature of a suspension of gold-nanoshell magnetic nanoeggs with surface-immobilized vancomycin (Van-Fe₃O₄@Au) rises from 23 to about 55 °C over 3 min under illumination by near-infrared (NIR) light (see picture). The cell growth of nosocomial pathogenic bacteria, including antibiotic-resistant strains, is targeted by the Van-Fe₃O₄@Au nanoeggs and can be effectively inhibited.

The hemolytic properties of amorphous silica and MCM-41-type mesoporous silica nanoparticles (MSNs) with rabbit red blood cells (RBCs) are compared. The amorphous silica exhibits a high hemolytic activity toward the RBCs. In contrast, a high biocompatibility between the MSNs and the RBCs is observed. The low hemolytic activity of the MSNs offers promising potential for various in vivo biotechnological applications.

A nanolithographic technique, electrophoretic printing lithography (EPL), is developed to generate heterogeneous biomolecular nanopatterns. By applying electric potentials on metal nanoelectrodes on a stamp, charged nanoparticles coated with distinct biomolecules are assembled onto the nanoelectrodes by electrophoretic deposition to generate heterogeneous biomolecular nanopatterns, which can then be printed from the stamp to a biocompatible polymer film (see image).

Message in a bottle: Alkaline hydrothermal treatment of lysozyme–silica hybrid particles leads to cagelike hollow aluminosilicates (CHAs) with vermiculate through-holes in the shell. Biomacromolecules can be transported inside the CHA through these holes and encapsulated within the confined inner space by crosslinking in a ship-in-bottle manner (see picture).

Water-soluble silicon nanocrystals with oxide surface passivation are synthesized via a facile solution route. The nanocrystal (see image) exhibit strong and stable blue photoluminescence in water with a high quantum yield, of about 12% over 6 months, due to the recombination of electron–hole pairs across the Γ–Γ direct band gap and via the surface oxide-related radiative centers.

Wire transport: The diameter-dependent transport coefficients in InAs nanowires (see picture) are studied at equal vertical and lateral fields and at equal gate–source voltage (V_GS) sweep rates. Simulations with a one-dimensional Schrödinger–Poisson solver support the presence of an electron accumulation layer near the positive interface-state charges that lead to the observed trends.

Between the sheets: Polystyrene–polyacrylamide copolymer is covalently grafted onto graphene sheets by in situ living free-radical polymerization to give “amphiphilic” graphene nanoplatelets. The block copolymer disperses graphene nanoplatelets in a polar solvent (water; see picture, A versus C) and also stabilizes them in a nonpolar solvent (xylene; B versus D).

Polymer gels are selectively deposited on a pre-patterned substrate, making a microgel array. The microgel array (see image) can be crosslinked and selectively and reversibly functionalized by nanoparticles through complementary hydrogen-bonding interactions. A reusable polymer/nanoparticle composite microstructure pattern with fluorescent and magnetic properties is constructed through this method.

A new type of “lock-and-key” patterned surface consisting of dense arrays of microfabricated PDMS lens and bowl arrays (see image) without silanization for the wettability and switching of adhesive forces is presented. The microlens-arrayed surface (lock) shows a low contact angle and a high adhesive force following the Wenzel state, whilst the imprinted microbowl-arrayed surfaces (key), which were replicas of the microlenses, exhibit a high contact angle and an anti-adhesive behavior following the Cassie–Baxter state.

Disorderly conduct: Are optical spectroscopy and fluorescence microscopy able to tell us about the organization of conjugated polyelectrolyte chains attached to DNA at the nano-  and microscale? With help of a new two-dimensional polarization single-molecule spectroscopy technique, disordered H-aggregate-like assemblies are revealed (see picture).

Densely packed and aligned TiO₂ nanorods 800–1100 nm in length are produced by oblique-angle deposition on indium tin oxide conducting substrates and utilized for photoelectrochemical cells for hydrogen production. The TiO₂ nanorods (see image) have a tilt angle of 60 ° with respect to the substrate. Incident-photon-to-current-conversion efficiency is 79% at 350 nm due to vectorial charge transfer through the long axis of the TiO₂ nanorods to the back contact.

By attaining better control over the hydrodynamic forces of self-assembly at surfaces, temperature-enhanced solvent vapor annealing allowsthe self-assembly of polycyclic aromaticmolecules into large, ordered crystals featuring an edge-on columnar type of arrangement (see image), which differs from the morphologies obtained using conventional solution-processing methods. Novel C₃ symmetric hexa-peri-hexabenzocoronenes functionalized with alternating hydrophilic and hydrophobic side chains are used as model systems.

Rapid, precise fabrication of 3D tissue analogs is accomplished using a dynamic-masking technique for directing nonlinear photocrosslinking of protein molecules. Protein scaffolds, such as sectioned chimpanzee skulls (see image), are defined using tomographic or computed datasets and can be fashioned within tens of seconds. The ability to rapidly integrate designs using this approach to microfabrication offers a straightforward means for prototyping 3D cellular scaffolds.

The living image: Quantitative biodistribution of near-infrared-emitting quantum dots (QDs) is studied in mice by micro positron emission tomography. PEGylation (PEG = polyethylene glycol) and peptide coating slow QD uptake into liver, spleen, and bone. Small peptide-coated QDs are in part renally excreted (see picture; < indicates bladder uptake).