Small

Cover image for Vol. 7 Issue 15

August 8, 2011

Volume 7, Issue 15

Pages 2125–2262

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Nanopores: The Passage of Homopolymeric RNA through Small Solid-State Nanopores (Small 15/2011) (page 2125)

      Michiel van den Hout, Gary M. Skinner, Sven Klijnhout, Vincent Krudde and Nynke H. Dekker

      Article first published online: 3 AUG 2011 | DOI: 10.1002/smll.201190052

      Thumbnail image of graphical abstract

      The cover picture, prepared by Gary M. Skinner, depicts a single molecule of the RNA homopolymer poly(U) (green), as it is electrically driven through a molecular-sized (diameter ≈ 2 nm), solid-state nanopore etched into a 20-nm-thick silicon nitride membrane. The highly flexible molecule ‘crowds’ the pore entrance, in some cases preventing translocation and instead forming a coiled structure that leads to significant blockage of the ionic current passing through the nanopore. Many biotechnological applications of nanopores require them to operate on this size-scale, and therefore our understanding of how biopolymers behave under such conditions is critical. For more information, please read the Full Paper “The Passage of Homopolymeric RNA through Small Solid-State Nanopores” by N. H. Dekker and co-workers, beginning on page 2217.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Nanocomposites: Synthesis of Macroporous Calcium Carbonate/Magnetite Nanocomposites and their Application in Photocatalytic Water Splitting (Small 15/2011) (page 2126)

      Dominic Walsh, Yi-Yeoun Kim, Akina Miyamoto and Fiona C. Meldrum

      Article first published online: 3 AUG 2011 | DOI: 10.1002/smll.201190053

      Thumbnail image of graphical abstract

      The cover picture shows the formation of highly hydrated and metastable calcium carbonate (CaCO3·6H2O) crystals containing carboxylated dextran-stabilized magnetite (Fe3O4) nanoparticles. These crystals are microwave heated, the bound water and magnetite particles both acting as microwave absorbers. The water present is rapidly expelled as steam to form remarkable open-framework CaCO3 supports, decorated throughout with attached magnetite nanoparticles. These porous composite structures can act as functional catalysts, for example, as a self-buffering co-catalyst for visible light-driven water oxidation. For more information, please read the Communication “Synthesis of Macroporous Calcium Carbonate/Magnetite Nanocomposites and their Application in Photocatalytic Water Splitting” by D. Walsh, F. Meldrum, and co-workers, beginning on page 2168.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Contents: (Small 15/2011) (pages 2127–2132)

      Article first published online: 3 AUG 2011 | DOI: 10.1002/smll.201190054

  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Design and Application of Inorganic Nanoparticle Superstructures: Current Status and Future challenges (pages 2133–2146)

      Yan Gao and Zhiyong Tang

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100474

      Thumbnail image of graphical abstract

      Self-assembly of inorganic nanoparticles into functional superstructures have attracted a lot of attention recently. The combination of inorganic nanoparticles and polymers or DNA gives rise to various applications, for example, photonic storage material. This review summarizes the latest progress in terms of design and application of inorganic nanoparticle superstructures and proposes its future challenges.

  5. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Microcontact Printing: Dynamic Microcontact Printing for Patterning Polymer-Brush Microstructures (Small 15/2011) (page 2147)

      Tao Chen, Rainer Jordan and Stefan Zauscher

      Article first published online: 3 AUG 2011 | DOI: 10.1002/smll.201190055

      Thumbnail image of graphical abstract

      The image illustrates dynamic printing using a conventional PDMS stamp by moving or jumping the stamp during microcontact printing (μCP). This new strategy, denoted “dynamic μCP”, could be combined with SI-ATRP to fabricate new, complex (hierarchical and gradient) polymer-brush microstructures with a number of feature morphologies that do not exist on the original stamp. The advantage lies in being able to pattern a series of complex polymer-brush microstructures using a single stamp without sophisticated instrumentation. This allows the various printing conditions for the transfer of thiols onto metallic surfaces to be systematically established, and, further, it provides a point of departure to micro/nanofabrication applied not only to pattern polymer brushes, but also to other fields, such as selective wet etching or the deposition of different materials.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Dynamic Microcontact Printing for Patterning Polymer-Brush Microstructures (pages 2148–2152)

      Tao Chen, Rainer Jordan and Stefan Zauscher

      Article first published online: 20 MAY 2011 | DOI: 10.1002/smll.201100354

      Thumbnail image of graphical abstract

      A single, conventional poly(dimethylsiloxane) (PDMS) stamp is used under a dynamic microcontact printing (μCP) method, extended from a static one. This new approach is investigated and combined with surface-initiated atom-transfer radical polymerization (SI-ATRP) to fabricate complex patterned hierarchical and gradient polymer-brush microstructures with a number of different feature morphologies that do not exist on the original stamp without sophisticated instrumentation being necessary.

    2. Functional Hydrogel Density Patterns Fabricated by Dip-Pen Nanolithography and Photografting (pages 2153–2157)

      Tomas Rakickas, Emma M. Ericsson, Živilė Ruželė, Bo Liedberg and Ramūnas Valiokas

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201002278

      Thumbnail image of graphical abstract

      Fabrication of submicrometer-sized PEG hydrogel patterns by self-initiated photo­grafting and photopolymerization on molecular templates, made by dip-pen nanolithography on gold, is described. Well-defined hydrogel structures (line and dot arrays) with features protruding 10–15 nm above a homogeneous hydrogel background are obtained. They can be carboxylated and employed for obtaining reusable protein density nanoarrays.

    3. Exploiting Dimerization of Purely Peptidic Amphiphiles to Form Vesicles (pages 2158–2162)

      Thomas B. Schuster, Dirk de Bruyn Ouboter, Nico Bruns and Wolfgang Meier

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100701

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      Short, amphiphilic peptides self-assemble into vesicles due to dimerization. These additional interactions lead to the formation of stable peptide membranes. The vesicles demonstrate pH responsiveness and the ability to encapsulate hydrophobic and hydrophilic moieties within their structure, and therefore may be used as an advanced, biodegradable, drug-delivery system.

    4. A Light Trigger for DNA Nanotechnology (pages 2163–2167)

      Thortsen L. Schmidt, Martin B. Koeppel, Julie Thevarpadam, Diana P. N. Gonçalves and Alexander Heckel

      Article first published online: 3 JUN 2011 | DOI: 10.1002/smll.201100182

      Thumbnail image of graphical abstract

      DNA minicircles with light-activated ‘caged’ interaction modules—based either on sticky ends or G-quadruplex interactions—do not form dimers until they are irradiated with near-UV light (not harmful for DNA). This technology offers a level of spatiotemporal (hybridization) control for functional nanoarchitectures.

    5. Synthesis of Macroporous Calcium Carbonate/Magnetite Nanocomposites and their Application in Photocatalytic Water Splitting (pages 2168–2172)

      Dominic Walsh, Yi-Yeoun Kim, Akina Miyamoto and Fiona C. Meldrum

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100268

      Thumbnail image of graphical abstract

      Fabrication of a new macroporous calcium carbonate nanocomposite is demo­nstrated using calcium carbonate hexahydrate. Magnetite nanoparticles are incorporated into the highly hydrated carbonate precursor and microwaving is used to convert the crystals into polycrystalline, vaterite blocks with open nano­architectures and retention of the original dimensions. Co-catalyst activity of the composite material is demonstrated for photocatalytic water oxidations.

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Frontispiece
    7. Communications
    8. Full Papers
    1. Flexible ZnO–Cellulose Nanocomposite for Multisource Energy Conversion (pages 2173–2178)

      Ashavani Kumar, Hemtej Gullapalli, Kaushik Balakrishnan, Andres Botello-Mendez, Robert Vajtai, Mauricio Terrones and Pulickel M. Ajayan

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100458

      Thumbnail image of graphical abstract

      Nanocomposite films consisting of ZnO nanostructures embedded in common paper are used as energy-conversion devices. The paper matrix makes these devices flexible while retaining their mechanical strength. This composite material can transform multiple sources, such as mechanical and thermal energy, into electric power, to provide a simplified and cost-effective platform for scavenging energy for practical applications.

    2. Antibody Covalent Immobilization on Carbon Nanotubes and Assessment of Antigen Binding (pages 2179–2187)

      Enrica Venturelli, Chiara Fabbro, Olivier Chaloin, Cécilia Ménard-Moyon, Cristian R. Smulski, Tatiana Da Ros, Kostas Kostarelos, Maurizio Prato and Alberto Bianco

      Article first published online: 24 MAY 2011 | DOI: 10.1002/smll.201100137

      Thumbnail image of graphical abstract

      Antibody–carbon nanotube (Ab–CNT) conjugates are synthesized through two covalent approaches and then characterized. The interaction between anti-MUC1 Ab–CNT conjugates and the Ab antigen is monitored by the surface plasmon resonance technique. The results support the development of systems based on the targeting properties of CNTs functionalized with antibodies.

    3. One-Step High-Yield Aqueous Synthesis of Size-Tunable Multispiked Gold Nanoparticles (pages 2188–2194)

      Tapan K. Sau, Andrey L. Rogach, Markus Döblinger and Jochen Feldmann

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100365

      Thumbnail image of graphical abstract

      A facile, one-step, water-based, ‘seedless’ synthetic method produces multispiked gold nanoparticles in a very high yield (>90%). This method allows the tuning of the number and size of the spikes, the overall size of the particles, and therefore the localized surface plasmon resonances of the particles over the broad spectral range in the visible and near-infrared.

    4. Self-Aligned Sub-10-nm Nanogap Electrode Array for Large-Scale Integration (pages 2195–2200)

      Pingqi Gao, Qing Zhang, Hong Li and Mary B. Chan-Park

      Article first published online: 31 MAY 2011 | DOI: 10.1002/smll.201100448

      Thumbnail image of graphical abstract

      A nanometer-scale gap is created between two adjacent electrodes of the same or different metals. The gap size can be controlled from 60 nm down to 5 nm with high reproducibility through sidewall coverage in a self-aligned manner. This technique is fully compatible with microfabrication technology and can be implemented to fabricate nanogap electrode arrays for integration purposes.

    5. Facile Construction of Nanofibers as a Functional Template for Surface Boron Coordination Reaction (pages 2201–2209)

      Xiao-Ding Xu, Yan-Feng Chu, Chang-Sheng Chen, Jing-Xiao Chen, Si-Xue Cheng, Xian-Zheng Zhang and Ren-Xi Zhuo

      Article first published online: 4 JUL 2011 | DOI: 10.1002/smll.201002097

      Thumbnail image of graphical abstract

      Nanofibers self-assembled from peptidyl boronic acids are constructed as a functional template. Due to the presence of phenylboronic acid moieties on the surface of the nanofibers, boron coordination reaction occurs on the template of nanofibers, which leads to an increase of their width and roughness. The novel concept of post-self-assembly modification could lead to a new technique for using nanostructures.

    6. Nanogap Electrode Fabrication for a Nanoscale Device by Volume-Expanding Electrochemical Synthesis (pages 2210–2216)

      Ju-Hyun Kim, Hanul Moon, Seunghyup Yoo and Yang-Kyu Choi

      Article first published online: 24 MAY 2011 | DOI: 10.1002/smll.201002103

      Thumbnail image of graphical abstract

      Electrochemical deposition of platinum ions reduces the microgap size to the sub-50-nm range. Current compliance, a buffered resistor, and a symmetric deposition strategy are used to achieve high reliability and practicality in the fabrication of nanogap electrodes. As a possible application, an organic thin-film transistor using nanogap electrodes is also demonstrated.

    7. The Passage of Homopolymeric RNA through Small Solid-State Nanopores (pages 2217–2224)

      Michiel van den Hout, Gary M. Skinner, Sven Klijnhout, Vincent Krudde and Nynke H. Dekker

      Article first published online: 3 JUN 2011 | DOI: 10.1002/smll.201100265

      Thumbnail image of graphical abstract

      Very small nanopores with a diameter approaching the molecular scale are used to investigate the passage of long RNA homopolymers. The data reveal that the passage of RNA through such pores is not a straightforward matter, with various different event types manifesting themselves. The different event types are described and their physical origin is discussed in this work. The resulting insights are of direct interest for nanopore-based studies of RNA structure, while also applying generally to the use of molecular-scale pores for biomolecular studies.

    8. Water Transport and Purification in Nanochannels Controlled by Asymmetric Wettability (pages 2225–2231)

      Qinwen Chen, Lingyi Meng, Qikai Li, Dong Wang, Wei Guo, Zhigang Shuai and Lei Jiang

      Article first published online: 24 MAY 2011 | DOI: 10.1002/smll.201100287

      Thumbnail image of graphical abstract

      Single-walled carbon nanotubes asymmetrically modified with hydrophilic and hydrophobic groups at each tip are designed. Molecular dynamics simulations for water transport through these nanotubes show a reduced water density on the hydrophobic sides. The functionalized (8, 8) tube can act as an efficient water filter due to ion exclusion and the stable water column structure within it.

    9. Preclinical Evaluation of Raman Nanoparticle Biodistribution for their Potential Use in Clinical Endoscopy Imaging (pages 2232–2240)

      Cristina L. Zavaleta, Keith B. Hartman, Zheng Miao, Michelle L. James, Paul Kempen, Avnesh S. Thakor, Carsten H. Nielsen, Robert Sinclair, Zhen Cheng and Sanjiv S. Gambhir

      Article first published online: 24 MAY 2011 | DOI: 10.1002/smll.201002317

      Thumbnail image of graphical abstract

      The biodistribution of gold Raman nanoparticles is evaluated after either intravenous (IV) or intrarectal (IR) administration in mice by radiolabeling them with 64Cu and imaging them using microPET. Results show localized accumulation in the colon followed by the rapid excretion of nanoparticles after IR injection with no appreciable uptake in any other organ. However, after IV injection, the results show immediate and continuous accumulation in several organs (i.e., liver, spleen).

    10. Image-Guided Prostate Cancer Therapy Using Aptamer-Functionalized Thermally Cross-Linked Superparamagnetic Iron Oxide Nanoparticles (pages 2241–2249)

      Mi Kyung Yu, Dongkyu Kim, In-Hyun Lee, Jee-Soo So, Yong Yeon Jeong and Sangyong Jon

      Article first published online: 7 JUN 2011 | DOI: 10.1002/smll.201100472

      Thumbnail image of graphical abstract

      Aptamer-capturing oligonucleotide-conjugated SPION hybridizes with prostate-specific membrane antigen (PSMA) aptamer to produce preferential binding sites for doxorubicin molecules, and thus a prostate-tumor targeting theranostic agent for enabling ‘personalized medicine'. The in-vivo targeting efficacy and therapeutic ability are evaluated in LNCaP xenograft model.

    11. In-Situ Observation of Nucleation and Growth of PbSe Magic-Sized Nanoclusters and Regular Nanocrystals (pages 2250–2262)

      Kui Yu, Jianying Ouyang and Donald M. Leek

      Article first published online: 7 JUL 2011 | DOI: 10.1002/smll.201100457

      Thumbnail image of graphical abstract

      An indirect reaction pathway is proposed to be dominant for the formation of PbSe monomers, which involves the reaction between lead oleate and diphenyl/dioctyl/trioctylphosphine (TOP) leading to a Pb–P complex/intermediate, which then reacts with TOPSe. The degree of supersaturation of the PbSe monomer plays a critical role in the formation of PbSe regular nanocrystals (RNCs) and/or magic-sized nanocrystals (MSNCs). Surface-determined cluster–cluster aggregation is responsible for the quantized growth of the RNCs at the initial growth stage and for the MSNCs.

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