Small

Cover image for Vol. 7 Issue 5

March 7, 2011

Volume 7, Issue 5

Pages 549–693

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Polymeric Materials: Patterned Polymer Carpets (Small 5/2011) (page 549)

      Ihsan Amin, Marin Steenackers, Ning Zhang, René Schubel, André Beyer, Armin Gölzhäuser and Rainer Jordan

      Article first published online: 2 MAR 2011 | DOI: 10.1002/smll.201190012

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      The cover image shows an atomic force microscopy scan (x,y: 20 μm × 20 μm; z: 120 nm) of a patterned polymer carpet of poly(4-vinylpyridine) (P4VP). The P4VP carpet is prepared by surface-initiated photografting and photopolymerization (SIPGP) on a 1 nm thick chemically patterned and fully crosslinked nanosheet. Because of preferred grafting, the chemical pattern is amplified by SIPGP into a patterned polymer brush of controlled morphology. Exposure of the carpet to good/bad solvents (ethanol, water) results in polymer brush swelling/collapse and causes a distinct and fully reversible buckling of the entire carpet. Directional buckling is observed, which correlates directly to the patterns. It is also found that directional carpet buckling only occurs if the pattern size is of the same dimension as the buckling wavelength. For more information please read the Full Paper “Patterned Polymer Carpets” by A. Gölzhäuser, R. Jordan, and co-workers, beginning on page 683.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Nanowire Arrays: Intact Mammalian Cell Function on Semiconductor Nanowire Arrays: New Perspectives for Cell-Based Biosensing (Small 1/2011) (page 550)

      Trine Berthing, Sara Bonde, Claus B. Sørensen, Pawel Utko, Jesper Nygård and Karen L. Martinez

      Article first published online: 2 MAR 2011 | DOI: 10.1002/smll.201190013

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      The cover image shows an artistic illustration of a human embryonic kidney cell cultured on an array of semiconducting indium-arsenide nanowires. The combination of the false-colored scanning electron micrograph and a fluorescent cross-section of the cell illustrates the ability of mammalian cells to form a spontaneous and close interface with nanowires and how electron microscopy and fluorescence techniques can be combined to investigate how cell function is affected by this interface. The indium-arsenide material demonstrates both favorable electrical and optical properties and could be promising for nanowire-based intracellular electrical probing if shown to be biocompatible. For more information, please read the Full Paper “Intact Mammalian Cell Function on Semiconductor Nanowire Arrays: New Perspectives for Cell-Based Biosensing” by K. L. Martinez and co-workers beginning on page 640.

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Contents: (Small 5/2011) (pages 551–557)

      Article first published online: 2 MAR 2011 | DOI: 10.1002/smll.201190014

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Directed Fracture for the Fabrication of Free-Standing Multilayered Submicrometer Structures (pages 558–562)

      Roberto R. Robaina, María José López-Martínez, Jaume Esteve, Raquel Perez-Castillejos and José Antonio Plaza

      Article first published online: 24 JAN 2011 | DOI: 10.1002/smll.201001105

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      Microdevices are fractured at specific sites to fabricate free-standing multilayered submicrometer structures, which consist of the microdevice cross sections that become exposed after fracture. As determined by finite-element modeling, the microdevices feature a fracturing point where stress concentrates under applied pulling forces. The structures fabricated here have a core of phosphosilicate glass surrounded by a layer of polycrystalline silicon.

    2. Seeding of Silicon Wire Growth by Out-Diffused Metal Precipitates (pages 563–567)

      Vidya Ganapati, David P. Fenning, Mariana I. Bertoni, Chito E. Kendrick, Alexandria E. Fecych, Joan M. Redwing and Tonio Buonassisi

      Article first published online: 25 JAN 2011 | DOI: 10.1002/smll.201002250

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      Metals diffused into bulk silicon can be manipulated to out-diffuse and precipitate in microsized droplets at surfaces, allowing for subsequent silicon wire growth. This technique allows for both high-throughput and precision in the size and positions of metal droplets on the silicon surface.

    3. Efficient Cytosolic Delivery of siRNA Using HDL-Mimicking Nanoparticles (pages 568–573)

      Mi Yang, Honglin Jin, Juan Chen, Lili Ding, Kenneth K. Ng, Qiaoya Lin, Jonathan F. Lovell, Zhihong Zhang and Gang Zheng

      Article first published online: 27 JAN 2011 | DOI: 10.1002/smll.201001589

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      High-density lipoprotein (HDL)-mimicking peptide–phospholipid scaffold (HPPS) nanoparticles are used as a flexible and biocompatible nanocarrier for the delivery of small interfering RNA (siRNA). The direct cytosolic delivery ability of cholesterol-modified siRNA displayed by the nanoparticle results in the selective delivery of RNA interference (RNAi) to targeted cells. This provides a strategy to bypass endolysosomal trafficking, and makes HPPS a useful tool for therapeutic siRNA delivery.

    4. Room-Temperature Edge Functionalization and Doping of Graphene by Mild Plasma (pages 574–577)

      Toshiaki Kato, Liying Jiao, Xinran Wang, Hailiang Wang, Xiaolin Li, Li Zhang, Rikizo Hatakeyama and Hongjie Dai

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201002146

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      A direct correlation between carrier doping and selective edge functionalization is revealed for graphene treated with a mild NH3 plasma. Raman mapping analysis shows that the D-peak near the edge of the graphene sheet selectively increases after plasma treatment. Electrical measurements show that the Dirac point position of a graphene nanoribbon device shifts toward a negative gate-bias voltage.

    5. Hierarchically Mesoporous Hematite Microspheres and Their Enhanced Formaldehyde-Sensing Properties (pages 578–582)

      Dan Mao, Jianxi Yao, Xiaoyong Lai, Mei Yang, Jiang Du and Dan Wang

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201001728

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      Hierarchically mesoporous hematite microspheres composed of mesoporous nanoparticles with crystalline walls are successfully synthesized combining hierarchical self-assembly and heat- treatment processes. They exhibit high specific surface areas and enhanced formaldehyde-sensing properties.

    6. Fabrication, Transfer, and Transport Properties of Monolayered Freestanding Nanoparticle Sheets (pages 583–587)

      Jianhui Liao, Yuzhi Zhou, Chenliang Huang, Yin Wang and Lianmao Peng

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201002078

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      Freestanding nanoparticle sheets are prepared over the holes of a microgrid, and the arrays are transferred onto a solid substrate by a gas flow. The electronic transport properties of nano­particle sheets suspended over trenches are measured. The scaling exponent is found to be significantly different from that of substrate-supported nanoparticle arrays.

    7. Enabling Cargo-Carrying Bacteria via Surface Attachment and Triggered Release (pages 588–592)

      Rohan Fernandes, Mary Zuniga, Fritz R. Sassine, Mert Karakoy and David H. Gracias

      Article first published online: 2 FEB 2011 | DOI: 10.1002/smll.201002036

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      Motile bacteria are selectively attached to submicrometer-scale cargo immobilized on gold patterns on a silicon substrate using surface chemistry and the specificity of antibody-based capture. The bacteria–cargo conjugates can be released on-demand from the surface with benign chemicals, and the motile bacteria are observed to propel their cargo in solution.

    8. Coherent Modulation of Propagating Plasmons in Silver-Nanowire-Based Structures (pages 593–596)

      Zhipeng Li, Shunping Zhang, Naomi J. Halas, Peter Nordlander and Hongxing Xu

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201001775

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      A branched nanowire with two input terminals and one output terminal can serve as a modulator. The light emission from the output resulting from illumination of one input can be modulated by illumination at the other input. The physical mechanism underlying the modulation is constructive or destructive interference of the nanowire plasmons supported by the structure. This finding is of importance for the development of integrated plasmonic devices for information and communication technologies.

    9. Au-Doped Polyacrylonitrile–Polyaniline Core–Shell Electrospun Nanofibers Having High Field-Effect Mobilities (pages 597–600)

      Wei Wang, Zhenyu Li, Xiuru Xu, Bo Dong, Hongnan Zhang, Zhaojie Wang, Ce Wang, Ray H. Baughman and Shaoli Fang

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201001716

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      Au-doped polyacrylonitrile–polyaniline core–shell nanofibers are fabricated via electrospinning and subsequent gas-phase polymerization, providing a very high field-effect mobility of up to 11.6 cm2 V−1 s−1. This method is also suitable for other conducting polymers and may eventually lead to a new and simplified fabrication of high-performance polymer organic field-effect transistors.

    10. Magnetically Driven Single DNA Nanomotor (pages 601–605)

      Suwussa Bamrungsap, Joseph A. Phillips, Xiangling Xiong, Youngmi Kim, Hui Wang, Haipeng Liu, Arthur Hebard and Weihong Tan

      Article first published online: 27 JAN 2011 | DOI: 10.1002/smll.201001559

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      Magnetically driven DNA nanomotors: one end of a set of DNA hairpins is immobilized on a glass surface and the other is conjugated to magnetic particles. The DNA hairpin molecules are opened by an external magnetic field gradient, and subsequently closed through DNA hybridization after the removal of the magnetic field. The separation of the ends of the DNA hairpin during opening is interpreted as the power stroke of the nanomotor and the hybridization of the hairpin as the recovery stroke.

    11. Multiple-Step Phase Transformation in Silver Nanoplates Under High Pressure (pages 606–611)

      Yugang Sun, Wenge Yang, Yang Ren, Lin Wang and Changhui Lei

      Article first published online: 4 FEB 2011 | DOI: 10.1002/smll.201002201

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      Silver nanoplates with multiple twin planes parallel to their basal surfaces exhibit multiple steps of structural distortion and phase transformation under increasing external pressure in a diamond-anvil cell. The disappearance of local hexagonal close-packed lamellae and a transformation from face-centered cubic to face-centered tetragonal phase are observed.

  5. Frontispiece

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Nanodevices: Location of Biomarkers and Reagents within Agarose Beads of a Programmable Nano-bio-chip (Small 5/2011) (page 612)

      Jesse V. Jokerst, Jie Chou, James P. Camp, Jorge Wong, Alexis Lennart, Amanda A. Pollard, Pierre N. Floriano, Nicolaos Christodoulides, Glennon W. Simmons, Yanjie Zhou, Mehnaaz F. Ali and John T. McDevitt

      Article first published online: 2 MAR 2011 | DOI: 10.1002/smll.201190015

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      The frontispiece features a diagnostic assay that can operate at the point-of-need. In spite of their ultrasmall size and inexpensive cost, these nanodevice sensor ensembles exhibit excellent performance characteristics and compare favorably to their expensive counterparts. They can be used to create integrated separation, collection, and detection ensembles that serve as a basis for eliminating laboratory-confined systems. Beads are tailored to collect and report the presence of specific organisms and diseases. The bead arrays bridge the nano- and micrometer ranges and allow for information to flow efficiently from the micro- to macroscale. The collected digitized data can be analyzed at remote central sites and then used to enable more effective health management as well as aid in the early identification of various global health syndromes. For more information, please read the Full Paper “Location of Biomarkers and Reagents within Agarose Beads of a Programmable Bio-nano-chip” by J. T. McDevitt and co-workers, beginning on page 612.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Contents
    5. Communications
    6. Frontispiece
    7. Full Papers
    1. Location of Biomarkers and Reagents within Agarose Beads of a Programmable Bio-nano-chip (pages 613–624)

      Jesse V. Jokerst, Jie Chou, James P. Camp, Jorge Wong, Alexis Lennart, Amanda A. Pollard, Pierre N. Floriano, Nicolaos Christodoulides, Glennon W. Simmons, Yanjie Zhou, Mehnaaz F. Ali and John T. McDevitt

      Article first published online: 2 FEB 2011 | DOI: 10.1002/smll.201002089

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      Protein biomarker capture is achieved within the programmable nano-bio-chip system via a nanonet. The variables of bead density, antibody size/concentration, and antigen size are explored for molecular-level insight into signal generation within this high-performance sensor.

    2. Affibody-Functionalized Gold–Silica Nanoparticles for Raman Molecular Imaging of the Epidermal Growth Factor Receptor (pages 625–633)

      Jesse V. Jokerst, Zheng Miao, Cristina Zavaleta, Zhen Cheng and Sanjiv S. Gambhir

      Article first published online: 8 FEB 2011 | DOI: 10.1002/smll.201002291

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      Raman imaging of epidermal growth factor receptor (EGFR) in tissue cultures and tumors is accomplished via multimodal nanoparticles consisting of a gold core and a silica shell functionalized with a fluorophore, polyethylene glycol, and EGFR-specific affibodies. The nanoparticle preparation is validated with both cultured cells and explanted murine tumors and is an important step toward contrast-enhanced colonoscopy via the Raman modality.

    3. Local Surface Potential of π-Conjugated Nanostructures by Kelvin Probe Force Microscopy: Effect of the Sampling Depth (pages 634–639)

      Andrea Liscio, Vincenzo Palermo, Oliver Fenwick, Slawomir Braun, Klaus Müllen, Mats Fahlman, Franco Cacialli and Paolo Samorí

      Article first published online: 31 JAN 2011 | DOI: 10.1002/smll.201001770

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      The structural and electronic properties of conjugated nanostructures, important for organic electronics, are quantitatively studied using Kelvin probe force microscopy with spatial and voltage resolutions of a few nanometers and millivolts, respectively. A comprehensive model is presented describing the precise 3D surface-potential mapping in functional electroactive nano-objects such as ultrathin layers of poly(3-hexylthiophene) and needles of perylene-bis-dicarboximide.

    4. Intact Mammalian Cell Function on Semiconductor Nanowire Arrays: New Perspectives for Cell-Based Biosensing (pages 640–647)

      Trine Berthing, Sara Bonde, Claus B. Sørensen, Pawel Utko, Jesper Nygård and Karen L. Martinez

      Article first published online: 2 FEB 2011 | DOI: 10.1002/smll.201001642

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      Arrays of vertical indium–arsenide nanowires are interfaced with human embryonic kidney cells and rat embryonic dorsal root ganglion neurons. A selection of critical cell functions and pathways are shown not to be impaired, including cell adhesion, membrane integrity, intracellular enzyme activity, DNA uptake, cytosolic and membrane protein expression, and the neuronal maturation pathway.

    5. Minimally Stable Nanoparticle-Based Colorimetric Assay for Simple, Rapid, and Sensitive Antibody Structure and Activity Evaluation (pages 648–655)

      Jung-Reem Woo, Dong-Kwon Lim and Jwa-Min Nam

      Article first published online: 10 FEB 2011 | DOI: 10.1002/smll.201002080

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      A simple and rapid assay is developed that allows for the determination of antibody structure and activity using minimally stable gold nanoparticle (AuNP) probes. The addition of salt to a minimally stable particle solution expedites particle aggregation and a subsequent color change in the solution. This colorimetric assay is highly sensitive and the whole assay time is ≈25 min without any complicated instrumentation.

    6. Enhancement of Cellulolytic Enzyme Activity by Clustering Cellulose Binding Domains on Nanoscaffolds (pages 656–664)

      Do-Myoung Kim, Mitsuo Umetsu, Kyo Takai, Takashi Matsuyama, Nobuhiro Ishida, Haruo Takahashi, Ryutaro Asano and Izumi Kumagai

      Article first published online: 2 FEB 2011 | DOI: 10.1002/smll.201002114

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      Heteroclustering of recombinant cellu-lase modules on streptavidin and nanoparticles results in significant improvements in the enzyme’s degradation activity for water-insoluble substrates. The clustering of multiple cellulose-binding domains (CBDs) on CdSe nanoparticles generates a significant increase in activity relative to that of the native free enzyme. A new design for artificial cellulosomes with multiple CBDs on noncellulosome-derived scaffold structures is proposed.

    7. Ball-Milling Modification of Single-Walled Carbon Nanotubes: Purification, Cutting, and Functionalization (pages 665–674)

      Noelia Rubio, Chiara Fabbro, M. Antonia Herrero, Antonio de la Hoz, Moreno Meneghetti, Jose L. G. Fierro, Maurizio Prato and Ester Vázquez

      Article first published online: 2 FEB 2011 | DOI: 10.1002/smll.201001917

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      Relatively homogeously sized single-walled carbon nanotubes(SWNTs) can be obtained by cutting with a planetary mill. The optimized conditions produce highly dispersible SWNTs that can be efficiently functionalized in a variety of synthetic ways. The milling/cutting procedure compares very favorably with the most common way of purifying SWNTs, namely treatment with strong oxidizing acids, as clearly shown by Raman spectroscopy. Moreover a similar milling process can be used to functionalize and cut pristine SWNTs by one-step nitrene chemistry.

    8. A Nanochannel/Nanoparticle-Based Filtering and Sensing Platform for Direct Detection of a Cancer Biomarker in Blood (pages 675–682)

      Alfredo de la Escosura-Muñiz and Arben Merkoçi

      Article first published online: 4 FEB 2011 | DOI: 10.1002/smll.201002349

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      Anodized alumina membranes act as both sensing platforms and filters for the detection of proteins in blood samples. The cells in the blood do not penetrate inside the nanochannels. Gold-nanoparticle tags are used for the enhancement of immunoblocking.

    9. Patterned Polymer Carpets (pages 683–687)

      Ihsan Amin, Marin Steenackers, Ning Zhang, René Schubel, André Beyer, Armin Gölzhäuser and Rainer Jordan

      Article first published online: 29 DEC 2010 | DOI: 10.1002/smll.201001658

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      Surface-initiated polymerization on fully crosslinked and chemically patterned nanosheets results in patterned polymer carpets. Upon swelling of the grafted polymer brush layer, the pattern has a directive effect upon the buckling of the nanometer-thin carpet. The morphology changes are found to be fully reversible.

    10. Enhanced Field Emission and Improved Supercapacitor Obtained from Plasma-Modified Bucky Paper (pages 688–693)

      Soumyendu Roy, Reeti Bajpai, Navneet Soin, Preeti Bajpai, Kiran S. Hazra, Neha Kulshrestha, Susanta Sinha Roy, James A. McLaughlin and D. S. Misra

      Article first published online: 7 FEB 2011 | DOI: 10.1002/smll.201002330

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      Freestanding, verticalsingle-walled carbon nanotube microstructures are formed on the surface of bucky paper by plasma treatment. The shapes of the microstructures depend on the type of plasma used. The performance of the papers as field emitters and electrodes in supercapacitors improves significantly after the modification.

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