Small

Cover image for Small

June 2008

Volume 4, Issue 6

Pages 687–859

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Cover Picture: Small 6/2008

      Pierre-Olivier Mouthuy, Sorin Melinte, Yves Henri Geerts, Bernard Nysten and Alain Marie Jonas

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200890022

      Thumbnail image of graphical abstract

      The cover picture shows a 10 ×10 µm2 magnification of a spiderweb-shaped network of liquid-crystalline discotic phthalocyanines, as seen by atomic force microscopy. This peculiar pattern is obtained by creating a nanotemplate consisting of crisscrossed nanogrooves. When phthalocyanines are confined in such nanogrooves, sidewall interfacial tension makes the alignment of the discotic columns follow the tangential direction down to the micrometer scale. At small curvature radii, the bending energy overcomes the alignment energy and the columns misalign. This leads to a method allowing an estimation of their bending modulus. For more information, please read the Communication “Nanocontrolled Bending of Discotic Columns by Spiral Networks” by A. M. Jonas et al. beginning on page 728.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Contents: Small 6/2008 (pages 687–694)

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200890023

  3. News

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
  4. Review

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Microfluidics

      Microfluidic Synthesis of Nanomaterials (pages 698–711)

      Yujun Song, Josef Hormes and Challa S. S. R. Kumar

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200701029

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      The review: presented here provides up-to-date information and analysis on microfluidic synthesis of different types of nanomaterial (metallic nanoparticles, quantum dots, silica nanoparticles, etc.). Attempts are made to find explanations for the claimed control over particle size, size distribution, and crystal structure of nanomaterials, in relation to special features of microfluidic reactors.

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Cell labeling

      A Multimodal Targeting Nanoparticle for Selectively Labeling T Cells (pages 712–715)

      Jonathan Gunn, Herschel Wallen, Omid Veiseh, Conroy Sun, Chen Fang, Jianhong Cao, Cassian Yee and Miqin Zhang

      Article first published online: 4 JUN 2008 | DOI: 10.1002/smll.200701103

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      A nanoparticle system capable of selectively labeling and monitoring antigen-specific cytotoxic T lymphocytes (CTLs) by magnetic resonance imaging and fluorescence reporting is demonstrated. These targeting nanoparticles were functionalized with tumor-specific peptide-major histocompatibility complex (MHC) (see figure). TEM and fluorescence microscopy reveal nanoparticle binding to the CTL membrane.

    2. Organic electronics

      Side-Gated Transport in Focused-Ion-Beam-Fabricated Multilayered Graphene Nanoribbons (pages 716–720)

      Jean-François Dayen, Ather Mahmood, Dmitry S. Golubev, Isabelle Roch-Jeune, Philippe Salles and Erik Dujardin

      Article first published online: 6 MAY 2008 | DOI: 10.1002/smll.200700913

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      A resist-less nanofabrication method, based on focused ion beam lithography, for connecting and tailoring a nanometer-scale planar device in ultrathin graphitic disks is demonstrated by producing 50-nm-wide double side-gated transistor devices (see image). Experiments and theory suggest that the behavior of the nanoribbons can be interpreted as a Coulomb blockade in a linear array of tunnel junctions between graphene islands.

    3. In vitro toxicity

      Adsorption of Essential Micronutrients by Carbon Nanotubes and the Implications for Nanotoxicity Testing (pages 721–727)

      Lin Guo, Annette Von Dem Bussche, Michelle Buechner, Aihui Yan, Agnes B. Kane and Robert H. Hurt

      Article first published online: 26 MAY 2008 | DOI: 10.1002/smll.200700754

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      Hungry nanotubes: Single-walled carbon nanotubes (SWNTs) compete with cells by interacting with folate and other essential micronutrients in cell culture medium (see picture). Sequestering of folate can cause apparent toxicity even without direct nanotube–cell contact through a new “starvation” mechanism.

    4. Discotic columns

      Nanocontrolled Bending of Discotic Columns by Spiral Networks (pages 728–732)

      Pierre-Olivier Mouthuy, Sorin Melinte, Yves Henri Geerts, Bernard Nysten and Alain Marie Jonas

      Article first published online: 26 MAY 2008 | DOI: 10.1002/smll.200700939

      Thumbnail image of graphical abstract

      The anisotropic interfacial tension of discotic phthalocyanines is used to produce intentionally curved columns. When phthalocyanines are confined in a mesoscopic spiral network of nanogrooves (see figure), the alignment of the discotic columns follows the tangential direction down to the micrometer scale. Energetic aspects of the alignment process are discussed and the bending modulus of the columns is determined.

    5. Stressed nanotubes

      Enhanced Mechanical Properties of Prestressed Multi-Walled Carbon Nanotubes (pages 733–737)

      Zhiping Xu, Lifeng Wang and Quanshui Zheng

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200700678

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      The benefits of stress: Prestressed multi-walled carbon nanotubes (PMWNTs; see picture) have smaller interwall spacings than normal multi-walled nanotubes (MWNTs) and significantly enhanced mechanical properties. Molecular simulations show that a 20% reduction in interwall spacing increases the interwall shear strength by up to four orders of magnitude. The PMWNTs have a tensile strength and stiffness about 20% higher than those of normal MWNTs.

    6. Nanowires

      “Nanofingers” Based on Binary Gold–Polypyrrole Nanowires (pages 738–741)

      Valber A. Pedrosa, Xiliang Luo, Jared Burdick and Joseph Wang

      Article first published online: 6 JUN 2008 | DOI: 10.1002/smll.200800161

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      Round the bend: Reversible bending of conducting-polymer–gold nanowires is achieved by template synthesis and a selective coating process that leaves only one side of the polymer segment exposed. The bending motion of the resulting “nanofingers” can be tailored by adjusting the applied potential (see figure). This represents the smallest bending arm reported to date and the first example of electrochemically induced nanowire bending.

    7. Polyelectrolytes

      Direct Growth of Optically Stable Gold Nanorods onto Polyelectrolyte Multilayered Capsules (pages 742–745)

      Hye Young Koo, Won San Choi and Dong-Yu Kim

      Article first published online: 15 APR 2008 | DOI: 10.1002/smll.200800021

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      The versatile preparation of the polyelectrolyte multilayered capsules functionalized with gold nanorods (AuNRs) is described. By seed-mediated growth of AuNR directly onto the capsules, stable complexation of the AuNRs onto the capsules can be achieved (see image). The resulting capsules show improved optical stability over free AuNRs, as well as tunable optical property depending on aspect ratio of the AuNRs.

    8. Nanoparticle toxicity

      Analysis of the Toxic Mode of Action of Silver Nanoparticles Using Stress-Specific Bioluminescent Bacteria (pages 746–750)

      Ee Taek Hwang, Jin Hyung Lee, Yun Ju Chae, Yeon Seok Kim, Byoung Chan Kim, Byoung-In Sang and Man Bock Gu

      Article first published online: 4 JUN 2008 | DOI: 10.1002/smll.200700954

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      Every cell has a silver lining! The toxicity of Ag nanoparticles is investigated using a panel of recombinant bioluminescent bacteria. The presence of the nanoparticles leads to the production of a superoxide radical (see figure). Furthermore, the Ag nanoparticles damage the cellular membranes, causing a disruption in the ion efflux system. Thus, the cells cannot effectively extrude the Ag ions and, hence, Ag nanoparticles cause more damage than do Ag ions.

    9. Nanowires

      Interface and Wetting Layer Effect on the Catalyst-Free Nucleation and Growth of GaN Nanowires (pages 751–754)

      Toma Stoica, Eli Sutter, Ralph J. Meijers, Ratan K. Debnath, Raffaella Calarco, Hans Lüth and Detlev Grützmacher

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200700936

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      Nanowire growth: Catalyst-free growth of GaN nanowires on Si substrates (see image) is investigated by high-resolution transmission electron microscopy. Small GaN crystalline clusters are found on top of an interface amorphous layer. High-crystalline-quality vertical nanowires are grown on an amorphous oxide layer. These findings open new possibilities for nanowire growth on a variety of nonconventional substrates.

    10. Bioinspired synthesis

      Biomimetic Synthesis of Silica with Chitosan-Mediated Morphology (pages 755–758)

      Boxun Leng, Xin Chen, Zhengzhong Shao and Weihua Ming

      Article first published online: 4 JUN 2008 | DOI: 10.1002/smll.200700917

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      Spherical, tabular, unique carambola-like shaped silica particles (see figure) are produced by the mediation of chitosan, a natural polyelectrolyte with abundant hydroxyl and amino groups. The silica morphology depends on the incubation time of the chitosan solution with phosphate ions before silicification. A sheet of the carambola-like silica made in this way has a granular surface, which inspires an “assembly–aggregation–silicification” model.

    11. Quantum dots

      Water-Soluble Off–On Spin-Labeled Quantum-Dots Conjugate (pages 759–764)

      Wenbin Chen, Xin Wang, Xijuan Tu, Dejun Pei, Yue Zhao and Xiangqun Guo

      Article first published online: 26 MAY 2008 | DOI: 10.1002/smll.200700788

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      Engineering quantum dots (QDs) with a paramagnetic nitroxide radical tail yields a weakly fluorescent spin-labeled QD conjugate. Quenching of the intrinsic fluorescence of the QDs results from electron transfer between the QDs and nitroxide radical. Interestingly, when the paramagnetic properties of the nitroxide moiety are eliminated, the quenched fluorescence of QDs is readily restored, making the spin-labeled QDs sensitive to a biological antioxidant, vitamin C (Vc; see figure).

    12. Scanning probe microscopy

      Constrained Molecular Manipulation Mediated by Attractive and Repulsive Tip–Adsorbate Forces (pages 765–769)

      Natalia Martsinovich, Lev Kantorovich, Richard H. J. Fawcett, Martin J. Humphry and Peter H. Beton

      Article first published online: 26 MAY 2008 | DOI: 10.1002/smll.200700580

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      Forcing fullerenes forward! The tip of a scanning tunneling microscope induces the manipulation of a C60 molecule (see image), displacing it across a Si surface. The results imply that the molecule is stabilized at intermediate positions between the expected adsorption sites. This is attributed to the formation of tip–molecule covalent bonds, which, in combination with molecule–substrate interactions, result in quasi-continuous constrained manipulation of the molecule.

    13. Solar cells

      Enhanced Efficiency in Solid-State Dye-Sensitized Solar Cells Based on Fractal Nanostructured TiO2 Thin Films (pages 770–776)

      Polycarpos Falaras, Thomas Stergiopoulos and Dimitrios S. Tsoukleris

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200700347

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      Solar system: Fractal nanostructured titania thin films of low roughness, high complexity, and relatively broad particle distribution have been developed by condensation of titanium butoxide in an ethyl cellulose (EC) polymer matrix, the process being induced by alcoholysis in the absence of water (see picture). The films can be used to fabricate dye-sensitized solid-state solar cells with power conversion efficiencies as high as 6.55%.

    14. Quantum dots

      Photoluminescence Decay Dynamics of Thiol-Capped CdTe Quantum Dots in Living Cells under Microexcitation (pages 777–780)

      Yu Zhang, Lan Mi, Pei-Nan Wang, Si-Jia Lu, Ji-Yao Chen, Jia Guo, Wu-Li Yang and Chang-Chun Wang

      Article first published online: 24 APR 2008 | DOI: 10.1002/smll.200701034

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      A shorter lifetime: The photoluminescence (PL) lifetime of intracellular thiol-capped CdTe quantum dots (QDs) varies greatly depending on the intracellular environment. The fluorescence image shows localization of the QDs (red) and lysosomes (green) in a human hepatocellular carcinoma (QGY) cell. The PL decay of the QDs inside (P2) the lysosomes shows a shorter PL lifetime than that outside (P1) the lyosomes.

    15. Nanoparticle assemblies

      A Renewable SERS Substrate Prepared by Cyclic Depositing and Stripping of Silver Shells on Gold Nanoparticle Microtubes (pages 781–786)

      Tie Wang, Xiaoge Hu and Shaojun Dong

      Article first published online: 4 JUN 2008 | DOI: 10.1002/smll.200700888

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      By controlling the deposition and desquamation of silver shells, a renewable SERS nanoparticle microtube is prepared (see figure). The vibrational modes of dominated bands in SERS spectra correlate with the distribution of silver atoms on nanoparticles. Silver–gold microtubes with sharp-edge nanosheets exhibit the highest enhancement ability of SERS. A detection limit is down to 6.0 × 10−12M is possible for 4-ATP.

  6. Full Papers

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Quantum dots

      Anomalous Photoluminescence in CdSe Quantum-Dot Solids at High Pressure Due to Nonuniform Stress (pages 788–794)

      Christian D. Grant, Jonathan C. Crowhurst, Sebastien Hamel, Andrew J. Williamson and Natalia Zaitseva

      Article first published online: 15 MAY 2008 | DOI: 10.1002/smll.200701097

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      When the pressure's on: Fluorescence from CdSe quantum dot solids (see picture) in environments varying from hydrostatic to highly nonhydrostatic show that small deviations from a uniform stress distribution greatly affect the electronic properties. The results are confirmed by all-atom theoretical calculations. Nonuniform stress must be considered when studying potentially pressure-mediated phenomena.

    2. Nanoelectronics

      Chemoselective Nanowire Fuses: Chemically Induced Cleavage and Electrical Detection of Carbon Nanofiber Bridges (pages 795–801)

      Bo Li, Lu Shang, Matthew S. Marcus, Tami Lasseter Clare, Edward Perkins and Robert J. Hamers

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200700944

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      Blowing a carbon nanofuse! A chemoselective nanowire fuse can be formed using molecular structures to link nanowires across a pair of electrodes. Exposure to the target molecule cleaves the molecular groups, releasing the nanowire (see figure). Real-time electrical detection results in a discrete, digital-like decrease in current.

    3. Tunable capacitors

      Nanomosaic Network for the Detection of Proteins Without Direct Electrical Contact (pages 802–809)

      Jean Gamby, Jean-Pierre Abid, Bernard Tribollet and Hubert H. Girault

      Article first published online: 17 APR 2008 | DOI: 10.1002/smll.200700778

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      Losing touch: A polymer microchip comprising two planar microelectrodes coupled to a nanomosaic system allows the detection of ultralow concentrations of biomolecules through capacitive couplings (see picture). This system behaves like a tunable capacitor and can be employed for the detection of subfemtomolar concentrations of proteins, such as β-lactoglobulin B.

    4. Nanobiotechnology

      Enzymatic Cleavage of Nucleic Acids on Gold Nanoparticles: A Generic Platform for Facile Colorimetric Biosensors (pages 810–816)

      Weian Zhao, Jeffrey C. F. Lam, William Chiuman, Michael A. Brook and Yingfu Li

      Article first published online: 6 JUN 2008 | DOI: 10.1002/smll.200700757

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      The removal of nucleic acid strands from gold nanoparticle surfaces by enzymatic cleavage results in a red-to-purple color change (see image) at a chosen salt concentration. This principle can be applied for the design of facile colorimetric biosensors to assess the activity of DNA-or RNA-cleaving enzymes and detect metal ions.

    5. Nanotube toxicity

      Low Inflammatory Activation by Self-Assembling Rosette Nanotubes in Human Calu-3 Pulmonary Epithelial Cells (pages 817–823)

      W. Shane Journeay, Sarabjeet S. Suri, Jesus G. Moralez, Hicham Fenniri and Baljit Singh

      Article first published online: 5 JUN 2008 | DOI: 10.1002/smll.200700700

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      Toxicity of organic nanotubes: Rosette nanotubes (see C and D in figure) self-assemble from structures shown in A and B and may have a range of biomedical applications. It is found that the rosette nanotubes have low toxicity in human Calu-3 pulmonary epithelial cells. These experiments add to the burgeoning field of toxicology on the nanoscale.

    6. Antimicrobial surfaces

      Micro-organism-Triggered Release of Silver Nanoparticles from Biodegradable Oxide Carriers Allows Preparation of Self-Sterilizing Polymer Surfaces (pages 824–832)

      Stefan Loher, Oliver D. Schneider, Tobias Maienfisch, Stefan Bokorny and Wendelin J. Stark

      Article first published online: 17 APR 2008 | DOI: 10.1002/smll.200800047

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      Self-sterilizing surfaces. Based on a detailed study of the mechanism of silver release in antimicrobial coatings, the activity of silver is improved by two to three orders of magnitude. Using the metabolism of growing bacteria as a trigger, polymer surfaces are designed that release silver nanoparticles only when required or stimulated by the presence of microorganism (see figure).

    7. Dendrimer-Grafted nanoparticles

      Convenient Synthesis and Properties of Polypropyleneimine Dendrimer-Functionalized Polymer Nanoparticles (pages 833–840)

      Chantal Larpent, Caroline Cannizzo, Anne Delgado, Fabrice Gouanvé, Paresh Sanghvi, Cédric Gaillard and Gérard Bacquet

      Article first published online: 4 JUN 2008 | DOI: 10.1002/smll.200701200

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      Shell suits: Stable, translucent aqueous suspensions of ultrafine, well-defined polymer particles coated with a polyamino dendritic shell are produced by covalent attachment of polypropylene imine (PPI) dendrimers on reactive nanoparticles (see picture). Their capacity to trap metal ions in the outer layer and their post-functionalization make these particles valuable building blocks for the elaboration of multifunctional or hybrid nanomaterials.

    8. Nanolithography

      Electron-Beam-Induced Deposition in Ultrahigh Vacuum: Lithographic Fabrication of Clean Iron Nanostructures (pages 841–846)

      Thomas Lukasczyk, Michael Schirmer, Hans-Peter Steinrück and Hubertus Marbach

      Article first published online: 6 MAY 2008 | DOI: 10.1002/smll.200701095

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      Naughts and crosses! A highly focused electron beam is used to locally crack adsorbed precursor (Fe(CO)5) molecules. The deposit generated at room temperature (RT, see image) consists ofpure iron nanodots with diameters<10 nm. The same shape written at 200 K results in a continuous nanostructure, an effect explained by the differentmobilities of the species.

    9. Biomolecule nanoarrays

      Atomic Force Microscopy-Derived Nanoscale Chip for the Detection of Human Pathogenic Viruses (pages 847–854)

      Helga Artelsmair, Ferry Kienberger, Ali Tinazli, Robert Schlapak, Rong Zhu, Johannes Preiner, Juergen Wruss, Markus Kastner, Nadia Saucedo-Zeni, Martin Hoelzl, Christian Rankl, Werner Baumgartner, Stefan Howorka, Dieter Blaas, Hermann J. Gruber, Robert Tampé and Peter Hinterdorfer

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200700691

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      Using AFM-based native protein nanolithography, nanopatterns of virus receptor molecules are deposited into an anti-adsorptive protein layer (see figure). Single virus particles are then affinity-captured onto the array, as shown by topographical AFM. Both the fabrication of and readout from the nanoscaled chip are conducted under native conditions. The nanoarray of viral receptors appears well-suited for the detection of single virus particles without prelabeling and preamplification.

  7. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
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  8. Keywords

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Keywords Index Small 6/2008 (page 856)

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200890024

  9. Authors

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. Authors Index Small 6/2008 (page 857)

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200890025

  10. Preview

    1. Top of page
    2. Cover Picture
    3. Contents
    4. News
    5. Review
    6. Communications
    7. Full Papers
    8. Corrigendum
    9. Keywords
    10. Authors
    11. Preview
    1. You have free access to this content
      coming soon (page 859)

      Article first published online: 17 JUN 2008 | DOI: 10.1002/smll.200890026

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