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Cover image for Vol. 7 Issue 20

October 17, 2011

Volume 7, Issue 20

Pages 2817–2952

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Imaging: Exploring the Formation of Focal Adhesions on Patterned Surfaces Using Super-Resolution Imaging (Small 20/2011) (page 2817)

      Fan-Ching Chien, Chiung Wen Kuo, Zong-Han Yang, Di-Yen Chueh and Peilin Chen

      Version of Record online: 12 OCT 2011 | DOI: 10.1002/smll.201190076

      Thumbnail image of graphical abstract

      The cover image illustrates the formation of focal adhesions on fibronectin nanopatterns as revealed by super-resolution imaging. The localization-based super-resolution imaging technique was employed to determine the position and density of vinculin proteins in the focal adhesions. A characteristic distance of 50 nm was found between vinculin molecules in the focal adhesions, which did not depend on the size of the fi bronectin nanopatterns; this distance is crucial for the formation of focal adhesions. In addition, the density of vinculin at the focal adhesions formed on the nanopatterns increased as the pattern size decreased. For more information, please read the Full Paper “Exploring the Formation of Focal Adhesions on Patterned Surfaces using Super- Resolution Imaging” by P. Chen and co-workers, starting on page 2906.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Nanowire Switches: Resistive-Switching Crossbar Memory Based on Ni–NiO Core–Shell Nanowires (Small 20/2011) (page 2818)

      Carlo Cagli, Federico Nardi, Bruce Harteneck, Zhongkui Tan, Yuegang Zhang and Daniele Ielmini

      Version of Record online: 12 OCT 2011 | DOI: 10.1002/smll.201190077

      Thumbnail image of graphical abstract

      The cover picture features a resistive switching memory nanodevice based on core-shell nanowires (NWs). The background image shows as-grown Ni NWs in an anodized aluminum oxide (AAO) template. Core-shell NWs are obtained by electrodeposition of Ni NWs within an AAO template and subsequent surface oxidation to form the active oxide shell. The resulting NW has a Ni core and a NiO shell, a known oxide suitable for a metal-insulator transition in resistive switching. Nanodevices like the one in the figure are obtained by magnetically assisted assembly and electrode formation by electron-beam lithography. Nonvolatile resistance switching with a resistance window of more than 5 decades is obtained, evidencing the metal-insulator transition at the cross-point junction between the two core-shell NWs. For more information, please read the Full Paper, “Resistive- Switching Crossbar Memory Based on Ni-NiO Core-Shell Nanowires” by Y. Zhang, D. Ielmini, and co-workers, starting on page 2899.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. In Situ Imaging of Multiphase Bio-interfaces at the Micro-/Nanoscale (pages 2825–2835)

      Peipei Chen, Lei Jiang and Dong Han

      Version of Record online: 20 SEP 2011 | DOI: 10.1002/smll.201100039

      Thumbnail image of graphical abstract

      Imaging multiphase bio-interfaces at the micro-/nanoscale is key for comprehending structure–function mechanisms. Developing techniques such as AFM and ESEM, and recent results of in situ imaging of multiphase systems, such as air/water/solid (left) and oil/water/solid (right) systems with three phases, are presented. This should help open doors to the invisible and hidden interfacial world.

  5. Essay

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Nanoscience and Nanotechnology: Evolving Definitions and Growing Footprint on the Scientific Landscape (pages 2836–2839)

      Michael L. Grieneisen and Minghua Zhang

      Version of Record online: 19 AUG 2011 | DOI: 10.1002/smll.201100387

      Thumbnail image of graphical abstract

      The consensus definition of “nanotechnology” today includes many structures with no dimension <100 nm. Web of Science now adds nearly 90 000 nanotechnology articles per year, including alarming proportions of all records in subject categories within physics, chemistry, and materials science. China has surpassed the USA, and >10% of all scholarly output from several Asian countries is now nanotechnology.

  6. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Self-Assembly: Self-Assembly and Microstructural Control of a Hexa-peri-hexabenzocoronene–Perylene Diimide Dyad by Solvent Vapor Diffusion (Small 20/2011) (page 2840)

      Suhao Wang, Lukas Dössel, Alexey Mavrinskiy, Peng Gao, Xinliang Feng, Wojciech Pisula and Klaus Müllen

      Version of Record online: 12 OCT 2011 | DOI: 10.1002/smll.201190074

      Thumbnail image of graphical abstract

      Control over the microstructure of solution-processed organic semiconductors on surfaces is crucial for charge carrier transport throughout the thin layer and for device performance. The image shows an AFM image of a large-scale, well-ordered, uniform surface microstructure of a liquid crystalline hexa-peri-hexabenzocoronene-perylene diimide dyad obtained via solvent vapor diffusion, a versatile and powerful processing method employed for the first time. With its large variety of processing parameters, SVD opens up the opportunity to finely balance solvent evaporation rate, dewetting effects, and various interactions, enabling the achievement of the desired molecular organization in thin-film layers. The topography image was acquired for a cyclohexane solution drop cast on HMDS in THF vapor atmosphere

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Self-Assembly and Microstructural Control of a Hexa-peri-hexabenzocoronene–Perylene Diimide Dyad by Solvent Vapor Diffusion (pages 2841–2846)

      Suhao Wang, Lukas Dössel, Alexey Mavrinskiy, Peng Gao, Xinliang Feng, Wojciech Pisula and Klaus Müllen

      Version of Record online: 7 SEP 2011 | DOI: 10.1002/smll.201100730

      Thumbnail image of graphical abstract

      Self-assembly and microstructural control of a hexa-peri-hexabenzocoronene–perylene diimide dyad are systematically studied by employing solvent vapor diffusion as a novel processing method. The influence of a variety of processing parameters on the microstructure and molecular organization at the surface is investigated. By manipulating the surface energy and solvent polarity, dewetting effects may be fine-tuned and the various interactions at the surfaces may be controlled.

    2. Engineering Fluorescence in Au-Tipped, CdSe-Seeded CdS Nanoheterostructures (pages 2847–2852)

      Sabyasachi Chakrabortty, Guichuan Xing, Yang Xu, Song Wee Ngiam, Nimai Mishra, Tze Chien Sum and Yinthai Chan

      Version of Record online: 24 AUG 2011 | DOI: 10.1002/smll.201100976

      Thumbnail image of graphical abstract

      Matchsticklike, Au-decorated, CdSe-seeded CdS nanorods are demonstrated as being able to retain a significant amount of their original fluorescence properties, exhibiting quantum yields of up to 23%. A proof-of-concept type application of these fluorescent metal-tipped semiconductor nanorods is given, exploiting the different chemical affinities of the metal and semiconductor moieties to facilitate directed assembly on a chemically patterned surface.

    3. Conduction Mechanisms and Environmental Sensitivity of Solution-Processed Silicon Nanoparticle Layers for Thin-Film Transistors (pages 2853–2857)

      Sebastian Weis, Richard Körmer, Michael P. M. Jank, Martin Lemberger, Michael Otto, Heiner Ryssel, Wolfgang Peukert and Lothar Frey

      Version of Record online: 22 AUG 2011 | DOI: 10.1002/smll.201100703

      Thumbnail image of graphical abstract

      Room-temperature, solution-processed, silicon nanoparticle thin films show significant gating with distinct hysteresis in their current–voltage characteristics. Device performance strongly depends on measurement environment and charge transport is determined by particle surfaces. Particle encapsulation with polymethyl methacrylate or Al2O3 reduces hysteresis and device sensitivity against environmental influences. Both Al2O3 coating and UV exposure during measurements alter current transport and enhance conductivity, providing evidence for surface-dominated transport.

    4. Detection of Nanoparticle Endocytosis Using Magneto-Photoacoustic Imaging (pages 2858–2862)

      Min Qu, Mohammad Mehrmohammadi and Stanislav Emelianov

      Version of Record online: 12 SEP 2011 | DOI: 10.1002/smll.201100960

      Thumbnail image of graphical abstract

      The endocytosis of nanoparticles by cells is of significant interest in various biomedical applications, including drug delivery and targeted therapy. An approach is developed to noninvasively detect nanoparticle endocytosis by living cells using magneto-photoacoustic (MPA) imaging. Using macrophages, it is demonstrated that the nanoparticles endocytosed by cells generate significantly larger MPA signals than the same concentration of nanoparticles present in the vicinity of macrophages. Overall, MPA imaging can simultaneously detect both the delivery and cellular endocytosis of nanoparticles.

    5. Nanoengineered Films via Surface-Confined Continuous Assembly of Polymers (pages 2863–2867)

      Tor Kit Goh, Stefanie N. Guntari, Christopher J. Ochs, Anton Blencowe, Damien Mertz, Luke A. Connal, Georgina K. Such, Greg G. Qiao and Frank Caruso

      Version of Record online: 24 AUG 2011 | DOI: 10.1002/smll.201101368

      Thumbnail image of graphical abstract

      A highly generalizable, surface-confined, continuous polymer assembly process, amenable to various substrates, reaction conditions and macromolecules, enables the synthesis of a range of nanoscale supported and freestanding cross-linked polymer films.

    6. Evolution of Gold Nanostructures on Graphene (pages 2868–2872)

      Recep Zan, Ursel Bangert, Quentin Ramasse and Konstantin S. Novoselov

      Version of Record online: 24 AUG 2011 | DOI: 10.1002/smll.201101169

      Thumbnail image of graphical abstract

      Gold clusters and individual atoms are seen on few-layer graphene in the scanning transmission electron microscopy high-angle annular dark-field (STEM-HAADF) image and individual atom positions are determined by the corresponding STEM bright-field image. The clusters nucleate exclusively in the hydrocarbon surface contamination. HAADF imaging is one of the most feasible methods to detect individual adatoms and impurities.

    7. Resolving In Situ Specific-Contact, Current-Crowding, and Channel Resistivity in Nanowire Devices: A Case Study with Silver Nanowires (pages 2873–2877)

      Maria M. Koleśnik, Stefan Hansel, Tarek Lutz, Niall Kinahan, Markus Boese and Vojislav Krstić

      Version of Record online: 8 SEP 2011 | DOI: 10.1002/smll.201100600

      Thumbnail image of graphical abstract

      Resistance contributions in a nanowire device are determined accurately. Resistance in silver nanowires, such as conduction-channel and contact resistance, including current-crowding effects, reveal both the true nanowire resistivity and the overall device performance, including dissipation and scaling potential. A comprehensive study on the device layout, the contact geometry and, most importantly, the transfer length over which charge injection between contact electrode and nanowire occurs, is performed.

  8. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Doped Nanoparticles: Evidence for Fe2+ in Wurtzite Coordination: Iron Doping Stabilizes ZnO Nanoparticles (Small 20/2011) (page 2878)

      Jianping Xiao, Agnieszka Kuc, Suman Pokhrel, Marco Schowalter, Satyam Parlapalli, Andreas Rosenauer, Thomas Frauenheim, Lutz Mädler, Lars G. M. Pettersson and Thomas Heine

      Version of Record online: 12 OCT 2011 | DOI: 10.1002/smll.201190075

      Thumbnail image of graphical abstract

      Zinc oxide nanoparticles can be stabilized by substitutional addition of iron, where up to 10% Fe2+ replace Zn2+ ions. The picture shows the transmission electron microscope image of a Fe-doped ZnO nanoparticle, decorated with the representation of the atomic positions of a computer simulation (Fe: yellow, Zn: blue, O: red). The samples have been characterized by TEM, PXRD, and ISEELS, and detailed density functional calculations confirm experimental observations: Fe ions stabilize the structure, the structural characteristics of the Fe-doped ZnO nanoparticles remain essentially unchanged, and comparison of experimental and simulated core-shell spectroscopy data exclude significant amounts of Fe3+ in the samples.

  9. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Essay
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Evidence for Fe2+ in Wurtzite Coordination: Iron Doping Stabilizes ZnO Nanoparticles (pages 2879–2886)

      Jianping Xiao, Agnieszka Kuc, Suman Pokhrel, Marco Schowalter, Satyam Parlapalli, Andreas Rosenauer, Thomas Frauenheim, Lutz Mädler, Lars G. M. Pettersson and Thomas Heine

      Version of Record online: 12 SEP 2011 | DOI: 10.1002/smll.201100963

      Thumbnail image of graphical abstract

      Flame spray pyrolysis allows the easy doping of ZnO nanoparticles (NPs) with other metals. Iron-doped ZnO is less toxic and less soluble than pure NPs. ZnO can be doped with up to 10 at% Fe without significant changes in the lattice. Fe2+ distributes homogeneously inside the NPs and substitutes Zn2+ ions at its lattice sites.

    2. Covalent Tethering of Protruding Arms for Addressable DNA Nanostructures (pages 2887–2898)

      Barbara Saccà and Christof M. Niemeyer

      Version of Record online: 8 SEP 2011 | DOI: 10.1002/smll.201101010

      Thumbnail image of graphical abstract

      A novel class of DNA tile motifs bears a covalently linked, single-stranded protruding arm. The increased flexibility of this arm enables efficient modification of tiles and superlattices with complementary DNA-linked objects and induces formation of partially folded bilayers which posses an intrinsic order at the ultrastructural level.

    3. Resistive-Switching Crossbar Memory Based on Ni–NiO Core–Shell Nanowires (pages 2899–2905)

      Carlo Cagli, Federico Nardi, Bruce Harteneck, Zhongkui Tan, Yuegang Zhang and Daniele Ielmini

      Version of Record online: 23 AUG 2011 | DOI: 10.1002/smll.201101157

      Thumbnail image of graphical abstract

      Self-assembled crossbar junctions featuring resistive switching are developed from core–shell nanowires. Ni nanowires (NWs) are first grown by electroplating in a template. The nanowires are then thermally oxidized to obtain the core–shell Ni–NiO structure, and crossbar junctions are developed by magnetic alignment and electron-beam lithography of the electrical contacts. Nonvolatile resistance switching with a resistance window of more than five decades is shown, which is evidence for metal–insulator transition at the cross-point junction between the two core–shell NWs.

    4. Exploring the Formation of Focal Adhesions on Patterned Surfaces Using Super-Resolution Imaging (pages 2906–2913)

      Fan-Ching Chien, Chiung Wen Kuo, Zong-Han Yang, Di-Yen Chueh and Peilin Chen

      Version of Record online: 22 AUG 2011 | DOI: 10.1002/smll.201100753

      Thumbnail image of graphical abstract

      Formation of focal adhesionson nanopatterned surfaces is investigated by super-resolution imaging. There exists a characteristic distance of 50 nm between vinculin molecules in focal adhesion, which is independent of pattern size. The density of vinculin molecules on nanopatterns increases as the pattern size decreases.

    5. Nanopatterning of Ferritin Molecules and the Controlled Size Reduction of Their Magnetic Cores (pages 2914–2920)

      Ramsés V. Martinez, Marco Chiesa and Ricardo Garcia

      Version of Record online: 16 AUG 2011 | DOI: 10.1002/smll.201100366

      Thumbnail image of graphical abstract

      Nanoscale-accurate microcontact printing over large areas with controlled dewetting is used to pattern ferritin. Magnetic force microscopy confirms that the magnetic properties of the iron oxide cores are conserved. Pyrolysis and plasma etching enable controlled size reduction of the nanoparticles.

    6. Synthesis of Silver Nanoparticle–Hollow Titanium Phosphate Sphere Hybrid as a Label for Ultrasensitive Electrochemical Detection of Human Interleukin-6 (pages 2921–2928)

      Juan Peng, Li-Na Feng, Zhong-Jie Ren, Li-Ping Jiang and Jun-Jie Zhu

      Version of Record online: 23 AUG 2011 | DOI: 10.1002/smll.201101210

      Thumbnail image of graphical abstract

      A simple ion-exchange process is used to synthesize silver nanoparticle–hollow titanium phosphate sphere hybrid material. This material shows good chemical stability, outstanding dispersity, and high silver loading. The hybrid can be used in a protein labeling system for immunoassay, which shows high sensitivity and low detection limit for the detection of human interleukin-6.

    7. A General Synthetic Approach for Obtaining Cationic and Anionic Inorganic Nanoparticles via Encapsulation in Amphiphilic Copolymers (pages 2929–2934)

      C. Geidel, S. Schmachtel, A. Riedinger, C. Pfeiffer, K. Müllen, M. Klapper and W. J. Parak

      Version of Record online: 29 AUG 2011 | DOI: 10.1002/smll.201100509

      Thumbnail image of graphical abstract

      A method for adjusting the charge of nanoparticles (NPs) to different negative and positive values by using polymers with a variable ratio of charged monomers and lauryl methacrylate is presented. Virtually all hydrophobic inorganic NPs could be coated with these amphiphilic polymers. This approach makes NPs available for use in many different studies that are designed to investigate charge-dependent processes.

    8. Reversible Pore-Structure Evolution in Hollow Silica Nanocapsules: Large Pores for siRNA Delivery and Nanoparticle Collecting (pages 2935–2944)

      Yu Chen, Chen Chu, Yuchuan Zhou, Yanfei Ru, Hangrong Chen, Feng Chen, Qianjun He, Yonglian Zhang, Linlin Zhang and Jianlin Shi

      Version of Record online: 8 SEP 2011 | DOI: 10.1002/smll.201101055

      Thumbnail image of graphical abstract

      The pore structure in the shell of nanosized hollow silica capsules is reversibly modulated by a facile, surfactant-directing, alkaline etching strategy. The large-sized pore hollow silica nanocapsules exhibit high siRNA loading capabilities and intracellular transfection efficiencies. In addition, they are shown to successfully capture and collect nanoparticles.

    9. Modulating the Charge-Transfer Enhancement in GERS using an Electrical Field under Vacuum and an n/p-Doping Atmosphere (pages 2945–2952)

      Hua Xu, Yabin Chen, Weigao Xu, Haoli Zhang, Jing Kong, Mildred S. Dresselhaus and Jin Zhang

      Version of Record online: 8 SEP 2011 | DOI: 10.1002/smll.201100546

      Thumbnail image of graphical abstract

      The modulation of charger-transfer (CT) enhancement in graphene-enhanced Raman scattering (GERS) by tuning the graphene Fermi level with an electric field in different atmospheres is presented. The Raman scattering intensities of molecules on graphene can be made strong or weak by applying an electric field, and the modulation behavior shows an obvious difference measured in ambient air, vacuum, NH3(n-doping) atmosphere, and O2(p-doping) atmosphere.

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