Small

Cover image for Vol. 8 Issue 19

October 8, 2012

Volume 8, Issue 19

Pages 2917–3061

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. DNA-Based Devices: Nanolattices of Switchable DNA-Based Motors (Small 19/2012) (page 2917)

      Barbara Saccà, Benjamin Siebers, Rebecca Meyer, Manfred Bayer and Christof M. Niemeyer

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290104

      Thumbnail image of graphical abstract

      The self-assembly properties of DNA are used by B. Saccà et al. to construct periodic arrays of switchable and optically traceable DNA motors. The reversible switching of Gquadruplex motifs between two well-defined conformational states, described on page 3000, is triggered by a specific hybridization event, which induces a linear translational movement, observable by FRET spectroscopy. This DNA-based nanoscaffolding strategy allows control over the distribution density of the motor moieties with nanometer precision. This is essential for the high efficiency of the system and for the generation of complex multi-responsive materials.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Hierarchical Structures: 3D Direct Laser Writing of Nano- and Microstructured Hierarchical Gecko-Mimicking Surfaces (Small 19/2012) (page 2918)

      Michael Röhrig, Michael Thiel, Matthias Worgull and Hendrik Hölscher

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290105

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      Adhesion of geckos, like this Tokay gecko, is based on the complex formation of delicate hairs covering their toes. 3D direct laser writing is the perfect tool to study such structures, as described by M. Rohrig, H. Holscher and co-workers on page 3009. Fabrication using 3D direct laser writing takes advantage of multiphoton absorption to create arbitrary micro- and nanostructures. The high flexibility of this rapid prototyping technique is exemplified with the presented “Small” logo: the width of the “l” in the logo is only 2.5 μm. Images copyright Eric Isselee, fivespots, KIT, 2012. Used under license from Shutterstock.com.

  3. Masthead

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Masthead: (Small 19/2012)

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290106

  4. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Contents: (Small 19/2012) (pages 2919–2924)

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290101

  5. Concepts

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Microfluidic Automation Using Elastomeric Valves and Droplets: Reducing Reliance on External Controllers (pages 2925–2934)

      Sung-Jin Kim, David Lai, Joong Yull Park, Ryuji Yokokawa and Shuichi Takayama

      Article first published online: 3 JUL 2012 | DOI: 10.1002/smll.201200456

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      In microfluidic devices, demands for the minimal use of external controllers while implementing high-throughput analysis are increasing. To this end, an overview of elastomeric valve- and droplet-based microfluidic systems is provided: the working principles and limitations of representative components in these devices along with relevant biochemical applications are discussed.

  6. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Hierarchical Structures: Macroscopic-Scale Alignment of Ultralong Ag Nanowires in Polymer Nanofiber Mat and Their Hierarchical Structures by Magnetic-Field-Assisted Electrospinning (Small 19/2012) (page 2935)

      Chuan-Ling Zhang, Kong-Peng Lv, Nai-Yin Hu, Le Yu, Xi-Feng Ren, Shi-Lin Liu and Shu-Hong Yu

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290102

      Thumbnail image of graphical abstract

      A facile approach to align Ag nanowires (AgNWs) on a macroscopic scale via a magnetic-field-assisted electrospinning technique is developed by S.-H. Yu and co-workers. The AgNWs assembled within the polymer fibers are arranged in parallel and can be further aligned by controlling the arrangement of the fibers into hierarchical structures, as described on page 2936. This method may provide a general way to assemble other nanowires within polymer nanofibers with controllable density on a macroscopic scale, especially for the combination of inorganic nanowires as fillers or functional components with flexible polymers.

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Macroscopic-Scale Alignment of Ultralong Ag Nanowires in Polymer Nanofiber Mat and Their Hierarchical Structures by Magnetic-Field-Assisted Electrospinning (pages 2936–2940)

      Chuan-Ling Zhang, Kong-Peng Lv, Nai-Yin Hu, Le Yu, Xi-Feng Ren, Shi-Lin Liu and Shu-Hong Yu

      Article first published online: 23 JUL 2012 | DOI: 10.1002/smll.201201353

      Thumbnail image of graphical abstract

      A facile approach for the macroscopic-scale alignment of Ag nanowires (AgNWs) by the magnetic-field-assisted electrospinning technique is reported. The AgNWs assemble within polymer fibers, such that they are all arranged parallel to each other throughout the sample. They can be further aligned into complex hierarchical structures by controlling the arrangement of the polymer fibers.

    2. High-Performance Inkjet Printed Carbon Nanotube Thin Film Transistors with High-k HfO2 Dielectric on Plastic Substrate (pages 2941–2947)

      Chun Wei Lee, Suresh Kumar Raman Pillai, Xuena Luan, Yilei Wang, Chang Ming Li and Mary B. Chan-Park

      Article first published online: 5 JUL 2012 | DOI: 10.1002/smll.201200041

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      Inkjet printing is used to fabricate CN-TFT devices on PET substrate with 70 nm HfO2 gate dielectric. By varying the amount of printing, effective mobility can be raised to 43 cm2 V−1 s−1 with on/off ratio ≥ 104 for devices with channel length 160 μm. This demonstrates that inkjet printing is promising for fabrication of high-performance devices in flexible electronics.

    3. Caged-Protein-Confined Bimetallic Structural Assemblies with Mimetic Peroxidase Activity (pages 2948–2953)

      Wei Zhang, Xiangyou Liu, Dominic Walsh, Siyu Yao, Yuan Kou and Ding Ma

      Article first published online: 9 JUL 2012 | DOI: 10.1002/smll.201102480

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      Protein-confined bimetallic structural ensembles with mimetic peroxidase activity are constructed. The oxidation reaction of 3,3,5,5-tetramethylbenzidine (TMB) with H2O2 is chosen to detect catalytic activity using UV–vis spectroscopy. The artificial enzyme is coupled with oxidase to build a dual-enzyme sensor system for the detection of biomolecules.

    4. Encapsulation of Self-Healing Agents in Polymer Nanocapsules (pages 2954–2958)

      Yi Zhao, Johannes Fickert, Katharina Landfester and Daniel Crespy

      Article first published online: 9 JUL 2012 | DOI: 10.1002/smll.201200530

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      Nanocapsules for the encapsulation of self-healing agents such as plasticizers, solvents, and monomers are prepared from various polymers. Successful encapsulation is driven by the internal phase separation between polymer and self-healing agent inthenanodroplets.

    5. Size-Controlled Single-Crystal Perovskite PbTiO3 Nanofibers from Edge-Shared TiO6 Octahedron Columns (pages 2959–2963)

      Zhenya Liu, Zhaohui Ren, Zhen Xiao, Chunying Chao, Xiao Wei, Yong Liu, Xiang Li, Gang Xu, Ge Shen and Gaorong Han

      Article first published online: 23 JUL 2012 | DOI: 10.1002/smll.201200795

      Thumbnail image of graphical abstract

      Tetragonal perovskite PbTiO3 nanofibers are prepared by a two-step method comprising synthesis of pre-perovskite (PP) PbTiO3 nanofibers by a hydrothermal method followed by annealing at 680 °C. Adjustment of the Pb/Ti molecular ratio in the hydrothermal reaction controls the size of the PP nanofibers and hence of the perovskite PbTiO3 nanofibers. Ferroelectric properties remain in fibers of diameter 13 nm.

    6. Experimental Confirmation of Local Field Enhancement Determining Far-Field Measurements with Shell-Isolated Silver Nanoparticles (pages 2964–2967)

      Ariel R. Guerrero, Yun Zhang and Ricardo F. Aroca

      Article first published online: 6 JUL 2012 | DOI: 10.1002/smll.201200750

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      The first direct experimental evidence for the dependence on the local field enhancement with Raman/fluorescence measurements in the far field is provided. This is achieved using shell-isolated silver nanoparticles permitting recording both the surface-enhanced Raman scattering (SHINERS) and surface-enhanced fluorescence (SHINEF) in one spectrum from a low quantum yield target molecule in solution. In addition, it is found that the SHINEF approach using shell-isolated silver nanoparticles provides enhancement factors much higher than those achieved with gold SHINs.

  8. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Templating: Substrate Templating upon Self-Assembly of Hydrogen-Bonded Molecular Networks on an Insulating Surface (Small 19/2012) (page 2968)

      Philipp Rahe, Markus Nimmrich and Angelika Kühnle

      Article first published online: 2 OCT 2012 | DOI: 10.1002/smll.201290103

      Thumbnail image of graphical abstract

      Extended hydrogen–bonded networks are formed by P. Rahe et al. after deposition of terephthalic and trimesic acid on the insulating calcite CaCO3(1014) surface. The self-assembled structures are stable at room temperature and no molecular dewetting is observed. A combined model of the molecular superstructures on the CaCO3(1014) surface. The left inset presents molecular double chains of terephthalic acid molecules, while the right depicts nearly hexagonal trimesic acid molecules. Single molecules are resolved in both images. A detailed analysis of the molecular structures on page 2969 reveals the significant influence of the underlying substrate, clearly indicating a substantial templating effect of the surface on the resulting molecular networks.

  9. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Frontispiece
    8. Communications
    9. Frontispiece
    10. Full Papers
    1. Substrate Templating upon Self-Assembly of Hydrogen-Bonded Molecular Networks on an Insulating Surface (pages 2969–2977)

      Philipp Rahe, Markus Nimmrich and Angelika Kühnle

      Article first published online: 6 JUL 2012 | DOI: 10.1002/smll.201200681

      Thumbnail image of graphical abstract

      Extended hydrogen-bonded networks are formed after deposition of terephthalic acid (left) and trimesic acid (right) on the insulating calcite CaCO3(equation image) surface. The self-assembled structures prove to be stable at room temperature, and of particular note is that no dewetting is observed. A detailed analysis of the molecular structures reveals a significant influence of the underlying substrate, clearly indicating a substantial templating effect of the surface on the resulting molecular networks.

    2. Control of Swelling of Responsive Nanogels by Nanoconfinement (pages 2978–2985)

      Stéphane Cuenot, Sadia Radji, Halima Alem, Sophie Demoustier-Champagne and Alain M. Jonas

      Article first published online: 8 JUN 2012 | DOI: 10.1002/smll.201200417

      Thumbnail image of graphical abstract

      Cylindrical nanogels are synthesized for different polymerization times within nanopores by using a template-based method. The swelling properties of individual thermoresponsive nanogels are investigated by atomic force microscopy as a function of both the water temperature and the confinement conditions. The nanoconfinement imposed during synthesis plays a key role in the maximum swelling of the nanogels.

    3. Nucleation-Controlled Distributed Plasticity in Penta-twinned Silver Nanowires (pages 2986–2993)

      Tobin Filleter, Seunghwa Ryu, Keonwook Kang, Jie Yin, Rodrigo A. Bernal, Kwonnam Sohn, Shuyou Li, Jiaxing Huang, Wei Cai and Horacio D. Espinosa

      Article first published online: 25 JUL 2012 | DOI: 10.1002/smll.201200522

      Thumbnail image of graphical abstract

      A unique plastic deformation mechanism in penta-twinned Ag nanowires is revealed through a combined experimental-computational approach. The coherent twin boundaries within the nanowires lead to size-dependant nucleation controlled plasticity for which thiner nanowires are found to exhibit a remarkable combination of high strength and ductility accompanied by distributed plastically deformed regions along the nanowires composed of stacking fault decahedron chains.

    4. Fabrication of Flexible MoS2 Thin-Film Transistor Arrays for Practical Gas-Sensing Applications (pages 2994–2999)

      Qiyuan He, Zhiyuan Zeng, Zongyou Yin, Hai Li, Shixin Wu, Xiao Huang and Hua Zhang

      Article first published online: 6 JUL 2012 | DOI: 10.1002/smll.201201224

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      By combining two kinds of solution-processable 2D materials, a flexible transistor array is fabricated in which a MoS2 thin film is used as the active channel and a reduced graphene oxide (rGO) film is used as the drain and source electrodes. This flexible transistor array can be used as a highly sensitive gas sensor with excellent reproducibility. Compared to using rGO thin film as the active channel, this new gas sensor exhibits much higher sensitivity. Moreover, functionalization of the MoS2 thin film with Pt nanoparticles further increases the sensitivity by up to ∼3 times.

    5. Nanolattices of Switchable DNA-Based Motors (pages 3000–3008)

      Barbara Saccà, Benjamin Siebers, Rebecca Meyer, Manfred Bayer and Christof M. Niemeyer

      Article first published online: 3 JUL 2012 | DOI: 10.1002/smll.201200703

      Thumbnail image of graphical abstract

      Ordered planar nanoarrays bearing DNA-responsive devices are produced by DNA self-assembly procedures. The nanomotors display extension and contraction movements in response to addition of DNA fuels with efficient cycling operation even after repetitive cycles. This DNA-based assembly of nanomechanical units offers full control over the spatial arrangement of each single molecule and opens the door to the development of more sophisticated nanomechanical devices.

    6. 3D Direct Laser Writing of Nano- and Microstructured Hierarchical Gecko-Mimicking Surfaces (pages 3009–3015)

      Michael Röhrig, Michael Thiel, Matthias Worgull and Hendrik Hölscher

      Article first published online: 6 JUL 2012 | DOI: 10.1002/smll.201200308

      Thumbnail image of graphical abstract

      Artificial hierarchical gecko-type structures with elastic moduli and length scales very close to those of the gecko's setae are designed by applying 3D direct laser writing. Measuring the adhesion by using atomic force microscopy with colloidal probes, it is shown that hierarchy is indeed favorable for artificial gecko-inspired dry adhesives made of stiff materials on the nanometer scale.

    7. Superparamagnetic Iron Oxide Nanoparticles (SPION) for the Treatment of Antibiotic-Resistant Biofilms (pages 3016–3027)

      Erik N. Taylor, Kim M. Kummer, Naside Gozde Durmus, Kohana Leuba, Keiko M. Tarquinio and Thomas J. Webster

      Article first published online: 6 JUL 2012 | DOI: 10.1002/smll.201200575

      Thumbnail image of graphical abstract

      The best treatment available clinically for managing infections is antibiotics, but resistant bacteria are becoming more prevalent. Moreover, biofilm formation on surfaces is another way that bacteria increase antibiotic resistances, and thus cause recurrent infections during antibiotic therapy. Antibacterial superparamagnetic iron oxide nanoparticles (SPION) developed here are a promising nanotechnology alternative for magnetic treatment of infectious biofilm-forming bacteria.

    8. Highly Luminescent–Paramagnetic Nanophosphor Probes for In Vitro High-Contrast Imaging of Human Breast Cancer Cells (pages 3028–3034)

      Bipin Kumar Gupta, Tharangattu N. Narayanan, Sajna Antony Vithayathil, Yean Lee, Shyny Koshy, Arava Leela Mohana Reddy, Avishek Saha, V. Shanker, V. N. Singh, Benny Abraham Kaipparettu, Angel A. Martí and Pulickel M. Ajayan

      Article first published online: 17 JUL 2012 | DOI: 10.1002/smll.201200909

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      A highly luminescent Y1.9O3:Eu0.13+ nanophosphor is synthesized using a modified sol–gel method. The nanophosphor produces both paramagnetic behavior and a highly efficient red emission peaking at 610 nm. Photoluminescence, time-resolvedspectroscopy, magnetization, cytotoxicity, and in vitro bioimaging studies in human breast cancer cells reveal that the nanophosphor could be applied to high-contrast bioimaging.

    9. Simultaneous Observation of the Lever Arm and Head Explains Myosin VI Dual Function (pages 3035–3040)

      Keigo Ikezaki, Tomotaka Komori, Mitsuhiro Sugawa, Yoshiyuki Arai, So Nishikawa, Atsuko H. Iwane and Toshio Yanagida

      Article first published online: 9 JUL 2012 | DOI: 10.1002/smll.201200765

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      Myosin VI steps are highly constrained by the forward tilt of the lever arm domains, as this tilt allows a single backward step from the distant binding state, prohibiting backward step generation from the adjacent binding state. Such constraints are important for achieving myosin VI's dual function.

    10. Characterization of Differential Toll-like Receptor Responses below the Optical Diffraction Limit (pages 3041–3049)

      Jesse S. Aaron, Bryan D. Carson and Jerilyn A. Timlin

      Article first published online: 17 JUL 2012 | DOI: 10.1002/smll.201200106

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      A dual-color stochastic optical reconstruction microscopy technique is employed to gain insight into the nanoscale organization of the innate immune system receptor TLR4. Data indicate significant changes in TLR4 clustering behavior within the cell membrane in response to immunostimulatory and immunoevading bacterial antigens, thereby shedding light on virulence mechanisms of highly pathogenic microbes such as Yersinia pestis.

    11. Microarray with Micro- and Nano-topographies Enables Identification of the Optimal Topography for Directing the Differentiation of Primary Murine Neural Progenitor Cells (pages 3050–3061)

      Aung Aung Kywe Moe, Mona Suryana, Guillaume Marcy, Sandy Keat Lim, Soneela Ankam, Jerome Zhi Wen Goh, Jing Jin, Benjamin Kim Kiat Teo, Jaslyn Bee Khuan Law, Hong Yee Low, Eyleen L. K. Goh, Michael P. Sheetz and Evelyn K. F. Yim

      Article first published online: 16 JUL 2012 | DOI: 10.1002/smll.201200490

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      A multi-architecture chip (MARC) is designed for studying cell–topography interaction more efficiently, based on the simple arithmetic of the patterned area and typical cell area. The MARC is fabricated to incorporate a vast range of topographies with different aspect ratios and different heights to enable rapid high-throughput screening for desired biological applications.

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