Small

Cover image for Vol. 7 Issue 8

April 18, 2011

Volume 7, Issue 8

Pages 981–1135

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Carbon Nanotubes: Biocompatibility of Immobilized Aligned Carbon Nanotubes (Small 8/2011) (page 981)

      David A. X. Nayagam, Richard A. Williams, Jun Chen, Kylie A. Magee, Jennifer Irwin, Justin Tan, Peter Innis, Ronald T. Leung, Sue Finch, Chris E. Williams, Graeme M. Clark and Gordon G. Wallace

      Article first published online: 14 APR 2011 | DOI: 10.1002/smll.201190025

      Thumbnail image of graphical abstract

      The cover picture shows a photomicrograph of multiwalled carbon nanotubes (CNTs) implanted within skeletal muscle and viewed under refractive light. The vertically aligned CNTs are immobilized within a biopolymer. After twelve weeks of implantation, the muscle tissue around the implant was harvested and prepared for pathohistological analysis. During tissue processing, the biopolymer was dissolved and there was some artifactual separation of the material from the cavity edge when sectioned for microscopic examination. This procedure was developed to enable evaluation of the tissue reaction to the nanomaterials and the preservation of the surrounding striated muscle, as illustrated in this image. The narrow fibrous tissue band immediately adjacent to the CNTs, and devoid of the cross-striations of the skeletal muscle, indicates a minimal tissue response to the immobilized nanotubes. For more information, please read the Full Paper “Biocompatibility of Immobilized Aligned Carbon Nanotubes” by D. A. X. Nagayam, G. G. Wallace, and co-workers beginning on page 1035.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Patterning: Strategies for Patterning Biomolecules with Dip-Pen Nanolithography (Small 8/2011) (page 982)

      Chien-Ching Wu, David N. Reinhoudt, Cees Otto, Vinod Subramaniam and Aldrik H. Velders

      Article first published online: 14 APR 2011 | DOI: 10.1002/smll.201190026

      Thumbnail image of graphical abstract

      Dip-pen nanolithography is arguably one of the most eye-catching developments of the last decade in the micro- and nanoscale fields of research. The cover picture shows a top-view of a pyramid-shaped atomic force microscopy (AFM) tip that has been functionalized with a nanometer-sized porous structure and a fluorescent pattern created by the tip. The porous tip is created by layer-by-layer deposition of polyvinylpyridine and poly-acrylic acid, and it allows for good inking properties of proteins, e.g., red fluorescent proteins, which can be consecutively written on a surface while maintaining the integrity of the structures. Writing biomolecules can now be done following many different strategies, using bare AFM tips or functionalized ones. For more information, please read the Review “Strategies for Patterning Biomolecules with Dip-Pen Nanolithography” by V. Subramaniam, A. H. Velders, and co-workers beginning on page on page 989.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Contents: (Small 8/2011) (pages 983–988)

      Article first published online: 14 APR 2011 | DOI: 10.1002/smll.201190027

  4. Review

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Strategies for Patterning Biomolecules with Dip-Pen Nanolithography (pages 989–1002)

      Chien-Ching Wu, David N. Reinhoudt, Cees Otto, Vinod Subramaniam and Aldrik H. Velders

      Article first published online: 14 MAR 2011 | DOI: 10.1002/smll.201001749

      Thumbnail image of graphical abstract

      Dip-pen nanolithography (DPN) has the ability to fabricate patterns on surfaces with a feature size down to ˜15 nm. This review describes the development of DPN and presents the related chemical strategies that have been reported to fabricate biomolecule patterns at micrometer and nanometer scale, classified into direct- and indirect DPN methodologies, discussing tip-functionalization strategies as well.

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Real-Time Monitoring of Solid-Phase PCR Using Fiber-Optic SPR (pages 1003–1006)

      Jeroen Pollet, Kris P. F. Janssen, Karel Knez and Jeroen Lammertyn

      Article first published online: 11 MAR 2011 | DOI: 10.1002/smll.201001984

      Thumbnail image of graphical abstract

      Real-time monitoring of solid-phase DNA amplification using a surface plasmon resonance sensor (SPR) with gold nanobead signal enhancement is presented. The sensor is applied in the quantification of a DNA aptamer and subsequent melting curve analysis. The system is suited for application in medical and food-safety diagnostics, and for the study and optimization of solid-phase polymerase chain reaction.

    2. Improvement of the Mechanical Properties of Epoxy by Peptide Nanotube Fillers (pages 1007–1011)

      Nitzan Even, Lihi Adler-Abramovich, Ludmila Buzhansky, Hanna Dodiuk and Ehud Gazit

      Article first published online: 21 MAR 2011 | DOI: 10.1002/smll.201001940

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      Remarkably rigid diphenylalanine peptide nanotubes are used as an organic nanofiller in an epoxy matrix, significantly increasing adhesive strength and toughness in addition to preserving the epoxy thermal and elongation properties. This effect exceeds the reinforcing effect of several known inorganic nanofillers, positioning the peptide nanotubes as an excellent nanofiller in composite materials.

    3. Ultrahigh External Quantum Efficiency from Thin SnO2 Nanowire Ultraviolet Photodetectors (pages 1012–1017)

      Linfeng Hu, Jian Yan, Meiyong Liao, Limin Wu and Xiaosheng Fang

      Article first published online: 30 MAR 2011 | DOI: 10.1002/smll.201002379

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      Thin SnO2 nanowires with uniform dia­meter and large surface-to-volume ratio are synthesized, and a single wire is used to fabricate a high-performance UV photodetector. An ultrahigh external quantum efficiency of 1.32 × 107 is achieved, which is about four orders of magnitude larger than that of conventional SnO2 photodetectors.

    4. Continuous Measurement of Atomic Force Microscope Tip Wear by Contact Resonance Force Microscopy (pages 1018–1022)

      Jason P. Killgore, Roy H. Geiss and Donna C. Hurley

      Article first published online: 15 MAR 2011 | DOI: 10.1002/smll.201002116

      Thumbnail image of graphical abstract

      Contact resonance force microscopy is used during AFM scanning to resolve instantaneous and progressive nanometer-scale changes in the contact radius between an AFM tip and a silicon substrate. High-resolution quantitative measurements of contact radius reveal real-time information on wear rate, fracture, and tip-symmetry.

    5. Effective-Tensional-Strain-Driven Bandgap Modulations in Helical Graphene Nanoribbons (pages 1023–1027)

      Dong-Bo Zhang and Traian Dumitrică

      Article first published online: 29 MAR 2011 | DOI: 10.1002/smll.201001890

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      Objective molecular dynamics simulations combined with an effective-tensional-strain concept provide a new theory for describing the electromechanical properties of nonideal twisted structures of graphene nanoribbons. It is shown that from the effective-strain perspective, the twist-induced bandgap modulations in graphene nanoribbons appear strikingly similar to those exhibited by the seamless carbon nanotubes.

  6. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. Self-Assembly: I-Motif Nanospheres: Unusual Self-Assembly of Long Cytosine Strands (Small 8/2011) (page 1028)

      Dragoslav Zikich, Ke Liu, Lior Sagiv, Danny Porath and Alexander Kotlyar

      Article first published online: 14 APR 2011 | DOI: 10.1002/smll.201190024

      Thumbnail image of graphical abstract

      The frontispiece shows pH-induced structural folding and unfolding of a homopolymeric DNA strand (poly(dC)), composed of hundreds of cytosine bases. Under mild acidic conditions (pH 4–5), poly(dC) folds into a compact spherical i-motif-based DNA nanostructure as revealed by atomic force microscopy. An increase in the pH from 4 to more than 7 leads to a reversible unfolding of the strand into the initial random-coil conformation. For more information, please read the Full Paper “I-Motif Nanospheres: Unusual Self-Assembly of Long Cytosine Strands” by D. Zikich, K. Liu, L. Sagiv, D. Porath,* and A. Kotlyar,* beginning on page 1028.

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Review
    6. Communications
    7. Frontispiece
    8. Full Papers
    1. I-Motif Nanospheres: Unusual Self-Assembly of Long Cytosine Strands (pages 1029–1034)

      Dragoslav Zikich, Ke Liu, Lior Sagiv, Danny Porath and Alexander Kotlyar

      Article first published online: 7 MAR 2011 | DOI: 10.1002/smll.201002213

      Thumbnail image of graphical abstract

      Under mild acidic conditions (pH 4–5), homopolymeric strands composed of hundreds of cytosine bases tend to fold into compact spherical i-motif-based DNA nanostructures, as revealed by atomic force microscopy. Increasing the pH beyond 7 results in reversible decomposition of the spherical nanostructures.

    2. Biocompatibility of Immobilized Aligned Carbon Nanotubes (pages 1035–1042)

      David A. X. Nayagam, Richard A. Williams, Jun Chen, Kylie A. Magee, Jennifer Irwin, Justin Tan, Peter Innis, Ronald T. Leung, Sue Finch, Chris E. Williams, Graeme M. Clark and Gordon G. Wallace

      Article first published online: 25 FEB 2011 | DOI: 10.1002/smll.201002083

      Thumbnail image of graphical abstract

      The response to chronically implanted aligned carbon nanotubes (ACNTs) held in position by a biopolymer membrane is investigated. Tissue surrounding the implant cavity is assessed for pathohistology and fibrosis. The recovered ACNT samples are examined with electron microscopy and immunohistochemistry. The results suggest that, while immobilized, ACNTs are inert and low-fouling with potential for future bionic components.

    3. Convective Assembly of 2D Lattices of Virus-like Particles Visualized by In-Situ Grazing-Incidence Small-Angle X-Ray Scattering (pages 1043–1050)

      Carlee E. Ashley, Darren R. Dunphy, Zhang Jiang, Eric C. Carnes, Zhen Yuan, Dimiter N. Petsev, Plamen B. Atanassov, Orlin D. Velev, Michael Sprung, Jin Wang, David S. Peabody and C. Jeffrey Brinker

      Article first published online: 21 MAR 2011 | DOI: 10.1002/smll.201001665

      Thumbnail image of graphical abstract

      The convective assembly of virus-like particles (VLPs) into highly ordered, oriented 2D superlattices is demonstrated, using grazing-incidence small-angle X-ray scattering (GISAXS) to confirm the formation of long-range order and to investigate the mechanism of self-assembly in situ. GISAXS data are consistent with a transport-limited assembly process; however addition of a nonvolatile solvent or assembly onto a chemically modified substrate altered this assembly pathway.

    4. Protein Nanocapsules Containing Doxorubicin as a pH-Responsive Delivery System (pages 1051–1060)

      Dongmei Ren, Felix Kratz and Szu-Wen Wang

      Article first published online: 29 MAR 2011 | DOI: 10.1002/smll.201002242

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      Cells incubated with free doxorubicin and protein nanoparticle-conjugated doxorubicin are imaged using confocal laser scanning microscopy, showing different internalization mechanisms and drug distributions.

    5. Nanoporous Elements in Microfluidics for Multiscale Manipulation of Bioparticles (pages 1061–1067)

      Grace D. Chen, Fabio Fachin, Marta Fernandez-Suarez, Brian L. Wardle and Mehmet Toner

      Article first published online: 17 MAR 2011 | DOI: 10.1002/smll.201002076

      Thumbnail image of graphical abstract

      Patterned carbon-nanotube forests as nanoporous elements in microfluidics are introduced for the enhancement of microscale bioseparation. The ultrahigh porosity of the forest enhances particle–surface interactions both for particles small enough to penetrate inside the forest and larger particles that flow around the forest. Mechanical and/or chemical capture of bioparticles ranging over three orders of magnitude in size is demonstrated.

    6. Stabilizing RNA by the Sonochemical Formation of RNA Nanospheres (pages 1068–1074)

      Ulyana Shimanovich, Vadim Volkov, Dror Eliaz, Adva Aizer, Shulamit Michaeli and Aharon Gedanken

      Article first published online: 29 MAR 2011 | DOI: 10.1002/smll.201002238

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      Long-term storable, biologically active RNA nanospheres are synthesized for the first time using sonochemical radiation. The RNA nanosphere formation is found to be a reversible process, and by using denaturing conditions, the RNA can be easily refolded into intact molecules.

    7. Assembly and Degradation of Low-Fouling Click-Functionalized Poly(ethylene glycol)-Based Multilayer Films and Capsules (pages 1075–1085)

      Melissa K. M. Leung, Georgina K. Such, Angus P. R. Johnston, Dhee P. Biswas, Zhiyuan Zhu, Yan Yan, Jean-François Lutz and Frank Caruso

      Article first published online: 21 MAR 2011 | DOI: 10.1002/smll.201002258

      Thumbnail image of graphical abstract

      Multilayer degradable PEG-based capsules are made of a nonlinear click- functionalized poly(ethylene glycol). These capsules exhibit excellent low-fouling behavior against human thrombi (blood clots). Together with the specific degradation characteristics, these properties make the PEG-based capsules promising for drug delivery applications.

    8. Proton Conductivity of SO3H-Functionalized Benzene–Periodic Mesoporous Organosilica (pages 1086–1097)

      Monir Sharifi, Christof Köhler, Pia Tölle, Thomas Frauenheim and Michael Wark

      Article first published online: 29 MAR 2011 | DOI: 10.1002/smll.201001931

      Thumbnail image of graphical abstract

      The proton conductivity of benzene– periodic mesoporous silica (PMO) materials functionalized with sulfonic acid groups is investigated using experimental and theoretical techniques. The SO3H functionalization of pristine benzene–PMO is realized by three different pathways based on a grafting method in which surface silanol groups and/or benzene rings are used to anchor SO3H groups for enhanced proton conductivity.

    9. Superiority of Branched Side Chains in Spontaneous Nanowire Formation: Exemplified by Poly(3-2-methylbutylthiophene) for High-Performance Solar Cells (pages 1098–1107)

      Hsieh-Chih Chen, I-Che Wu, Jui-Hsiang Hung, Fu-Je Chen, I-Wen P. Chen, Yung-Kang Peng, Chao-Sung Lin, Chun-Hsien Chen, Yu-Jane Sheng, Heng-Kwong Tsao and Pi-Tai Chou

      Article first published online: 21 MAR 2011 | DOI: 10.1002/smll.201002196

      Thumbnail image of graphical abstract

      Spontaneous and stable nanowire formation is probed by a combined theoretical and experimental approach. Highly dense P3MBT nanowires are blended with PC71BM in order to achieve short and continuous pathways in the photoactive layer, a key factor contributing to the high performance of bulk-heterojunction (BHJ) solar cells by facilitating efficient hole transfer. The optimum conversion efficiency and incident photon-to-current efficiency are 4.15% and 68% for the P3MBT:PC71BM device.

    10. Hierarchical Micro- and Mesoporous Carbide-Derived Carbon as a High-Performance Electrode Material in Supercapacitors (pages 1108–1117)

      Marcus Rose, Yair Korenblit, Emanuel Kockrick, Lars Borchardt, Martin Oschatz, Stefan Kaskel and Gleb Yushin

      Article first published online: 30 MAR 2011 | DOI: 10.1002/smll.201001898

      Thumbnail image of graphical abstract

      Ordered mesoporous carbide-derived carbon (OM-CDC) materials produced by nanocasting of ordered mesoporous silica templates showed fast rate capability and specific capacitance up to 200 F g−1 in aqueous electrolytes and ionic liquids. At room temperature, the enhanced ion transport in OM-CDC allowed up to 90% of the capacitance retention at current densities in excess of ∼10 A g−1.

    11. Classification NanoSAR Development for Cytotoxicity of Metal Oxide Nanoparticles (pages 1118–1126)

      Rong Liu, Robert Rallo, Saji George, Zhaoxia Ji, Sumitra Nair, André E. Nel and Yoram Cohen

      Article first published online: 24 MAR 2011 | DOI: 10.1002/smll.201002366

      Thumbnail image of graphical abstract

      A classification-based cytotoxicity nanostructure–activity realtionship (nanoSAR) is developed based on the exposure of BEAS-2B cells to metal oxide nanoparticles. Model development follows a rigorous workflow that includes strict model validation and applicability domain assessment. High classification accuracy (toxic versus nontoxic) is obtained with four fundamental model descriptors, suggesting the potential application of the approach for environmental impact analysis.

    12. LiFePO4 Mesocrystals for Lithium-Ion Batteries (pages 1127–1135)

      Jelena Popovic, Rezan Demir-Cakan, Julian Tornow, Mathieu Morcrette, Dang Sheng Su, Robert Schlögl, Markus Antonietti and Maria-Magdalena Titirici

      Article first published online: 30 MAR 2011 | DOI: 10.1002/smll.201002000

      Thumbnail image of graphical abstract

      A simple low-temperature routeto LiFePO4 with mesocrystalline morphology is presented. Electrochemical testing of pure LiFePO4 and its carbon-coated composites indicates that it is a potential cathode material for Li-ion batteries.

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