Small

Cover image for Vol. 8 Issue 16

August 20, 2012

Volume 8, Issue 16

Pages 2449–2607

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Mixed Valence Materials: Prussian Blue Analogues of Reduced Dimensionality (Small 16/2012) (page 2449)

      Régis Y. N. Gengler, Luminita M. Toma, Emilio Pardo, Francesc Lloret, Xiaoxing Ke, Gustaaf Van Tendeloo, Dimitrios Gournis and Petra Rudolf

      Article first published online: 8 AUG 2012 | DOI: 10.1002/smll.201290088

      Thumbnail image of graphical abstract

      The cover image shows an artistic view of the “on surface” synthesis of low-dimensional Prussian Blue Analogues (PBAs) on a layered aluminosilicate clay mineral. The network of spheres illustrates the innovative bi-dimensional arrangement of PBAs as synthesized in a self-limited cation exchange reaction on the clay surface. Well-packed clay platelet monolayers (visible in the blue background), deposited by a Langmuir–Schaefer approach, are used here as templates. This low-dimensional assembly preserves a high Tc of ∼80 K and gives rise to a new magnetic behavior between superparamagnetic and spin-glass properties. For more information, please refer to the Full Paper “Prussian Blue Analogues of Reduced Dimensionality” by F. Lloret, D. Gournis, P. Rudolf and co-workers, beginning on page 2532.

  2. Inside Front Cover

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Hydrogel Microstructures: Characterization of Mass and Swelling of Hydrogel Microstructures using MEMS Resonant Mass Sensor Arrays (Small 16/2012) (page 2450)

      Larry J. Millet, Elise A. Corbin, Robert Free, Kidong Park, Hyunjoon Kong, William P. King and Rashid Bashir

      Article first published online: 8 AUG 2012 | DOI: 10.1002/smll.201290089

      Thumbnail image of graphical abstract

      Through photolithography, poly(ethylene glycol)diacrylate microstructures can be attached to microelectromechanical system resonant mass sensor arrays to enable the characterization of hydrogel mass and swelling. Mass values obtained coincide with the values obtained through imaging-based measures of microstructure volume for independent mass determination. The data shown on page 2555 indicate a size-dependent increase in gel mass with increasing fluid density; volume comparisons of a range of bulk hydrogel concentrations (5% to 100% v/v) show a non-linear swelling trend.

  3. Masthead

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Masthead: (Small 16/2012)

      Article first published online: 8 AUG 2012 | DOI: 10.1002/smll.201290090

  4. Contents

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Contents: (Small 16/2012) (pages 2451–2457)

      Article first published online: 8 AUG 2012 | DOI: 10.1002/smll.201290087

  5. Concepts

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Assembly of Graphene Sheets into 3D Macroscopic Structures (pages 2458–2463)

      Shengyan Yin, Zhiqiang Niu and Xiaodong Chen

      Article first published online: 23 MAY 2012 | DOI: 10.1002/smll.201102614

      Thumbnail image of graphical abstract

      Integration of graphene sheets into 3D macroscopic assemblies and ultimately into a functional system is essential to explore the advanced properties of individual graphene sheets for macroscopic applications.

    2. Rational Design and Nanofabrication of Gecko-Inspired Fibrillar Adhesives (pages 2464–2468)

      Shihao Hu and Zhenhai Xia

      Article first published online: 29 MAY 2012 | DOI: 10.1002/smll.201200413

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      Mimicking gecko toe pad structure leads to the development of new types of fibrillar adhesives. Early attempts show a convergent design trend in replicating the geometric features of gecko foot hairs. Recently, combining other physical, chemical, and biological principles with gecko-inspired geometric merits opens up new doors toward smart adhesives with stimuli-responsive control, self-cleaning properties, and enhanced durability.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Tunable Biomolecular Interaction and Fluorescence Quenching Ability of Graphene Oxide: Application to “Turn-on” DNA Sensing in Biological Media (pages 2469–2476)

      Bong Jin Hong, Zhi An, Owen C. Compton and SonBinh T. Nguyen

      Article first published online: 14 JUN 2012 | DOI: 10.1002/smll.201200264

      Thumbnail image of graphical abstract

      As a platform for “turn-on” DNA sensing, the level of oxidation of graphene oxide strongly affects its fluorescence quenching ability and binding interactions to single-stranded oligodeoxyribonucleotides (ssODNs), leading to a broad range of sensitivity. Fine-tuning the level of oxidation of graphene oxide yields a DNA-detection platform that is highly sensitive in serum and biological media.

    2. Self-Assembled Magnetic Bead Biosensor for Measuring Bacterial Growth and Antimicrobial Susceptibility Testing (pages 2477–2482)

      Paivo Kinnunen, Brandon H. McNaughton, Theodore Albertson, Irene Sinn, Sima Mofakham, Remy Elbez, Duane W. Newton, Alan Hunt and Raoul Kopelman

      Article first published online: 5 JUN 2012 | DOI: 10.1002/smll.201200110

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      Bacterial antibiotic resistance is one of the major concerns of modern healthcare worldwide, and the development of rapid, growth-based, antimicrobial susceptibility tests is key for addressing it. The cover image shows a self-assembled asynchronous magnetic bead rotation (AMBR) biosensor developed for rapid detection of bacterial growth. Using the biosensors, the minimum inhibitory concentration of a clinical E. coli isolate can be measured within two hours, where currently tests take 6–24 hours. A 16-well prototype is also constructed for simple and robust observation of the self-assembled AMBR biosensors.

    3. Curved Biodegradable Microneedles for Vascular Drug Delivery (pages 2483–2488)

      Chang Kuk Choi, Jin Bum Kim, Eui Hwa Jang, Young-Nam Youn and Won Hyoung Ryu

      Article first published online: 25 MAY 2012 | DOI: 10.1002/smll.201200441

      Thumbnail image of graphical abstract

      Curved biodegradable microneedles for application to the outer surface of blood vessels are produced to enhance drug delivery to vascular tissues suffering from hyperplasia or atherosclerosis. Spatially discrete thermal drawing and post-annealing processes are employed to fabricate microneedles on a curved surface. Insertion of microneedles into arteries in vivo and ex vivo is demonstrated, and their mechanical properties and drug-delivery function are studied.

    4. Natural Bactericidal Surfaces: Mechanical Rupture of Pseudomonas aeruginosa Cells by Cicada Wings (pages 2489–2494)

      Elena P. Ivanova, Jafar Hasan, Hayden K. Webb, Vi Khanh Truong, Gregory S. Watson, Jolanta A. Watson, Vladimir A. Baulin, Sergey Pogodin, James Y. Wang, Mark J. Tobin, Christian Löbbe and Russell J. Crawford

      Article first published online: 4 JUN 2012 | DOI: 10.1002/smll.201200528

      Thumbnail image of graphical abstract

      Natural superhydrophobic surfaces are often thought to have antibiofouling potential due to their self-cleaning properties. However, when incubated on cicada wings, Pseudomonas aeruginosa cells are not repelled; instead they are penetrated by the nanopillar arrays present on the wing surface, resulting in bacterial cell death. Cicada wings are effective antibacterial, as opposed to antibiofouling, surfaces.

    5. In Vitro and In Vivo Interrogation of Bio-sprayed Cells (pages 2495–2500)

      Nuria Andreu, Dominique Thomas, Luisa Saraiva, Natalie Ward, Kenth Gustafsson, Suwan N. Jayasinghe and Brian D. Robertson

      Article first published online: 31 MAY 2012 | DOI: 10.1002/smll.201200138

      Thumbnail image of graphical abstract

      Bio-sprays can directly form pre-organized cell-bearing structures for applications ranging from engineering functional tissues to the forming of cultures, most useful for modeling disease, to the discovery and development of drugs. Bio-electrosprays and aerodynamically assisted bio-jets, are leading approaches that have been demonstrated as having far-reaching ramifications for regenerative biology and medicine.

    6. Ultrasmall Microlens Array Based on Vertically Aligned Carbon Nanofibers (pages 2501–2504)

      Qing Dai, Ranjith Rajasekharan, Haider Butt, Xiaohui Qiu, Gehan Amaragtunga and Timothy D. Wilkinson

      Article first published online: 14 JUN 2012 | DOI: 10.1002/smll.201200397

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      An ultrasmall tunable microlens with a diameter of 1.5 μm is fabricated using nematic liquid crystals (electrically tunable medium) and vertically aligned carbon nanofibers (CNFs, electrodes). Individual CNFs are grown at the center of circular dielectric regions. This allows the CNFs to produce a more Gaussian electric field profile and hence more uniformity in lens array switching.

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Front Cover
    4. Masthead
    5. Contents
    6. Concepts
    7. Communications
    8. Full Papers
    1. Epidermal Growth Factor–Ferritin H-Chain Protein Nanoparticles for Tumor Active Targeting (pages 2505–2514)

      Xu Li, Lihui Qiu, Pei Zhu, Xinyi Tao, Tadayuki Imanaka, Jing Zhao, Youguo Huang, Yaping Tu and Xuni Cao

      Article first published online: 23 MAY 2012 | DOI: 10.1002/smll.201200066

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      Epidermal growth factor (EGF)–human ferritin H-chain protein (FTH1) nanoparticles are prepared by using a genetic method. The EGF-FTH1 nanoparticles show a precisely assembled nanometer-scale structure, and small size with narrow size distribution. Due to specific binding to EGF receptor (EGFR)-positive cancer cells and the enhanced permeability and retention effect, in vivo tumor accumulation is observed.

    2. Cobalt-Mediated Crystallographic Etching of Graphite From Defects (pages 2515–2523)

      Rui Wang, Jiayi Wang, Hao Gong, Zhiqiang Luo, Da Zhan, Zexiang Shen and John T. L. Thong

      Article first published online: 27 APR 2012 | DOI: 10.1002/smll.201102747

      Thumbnail image of graphical abstract

      Cobalt-assisted crystallographic etching is explored to pattern graphene/graphite at predefined positions. The etching leaves well-defined zigzag edges oriented at 60° or 120° relative to each other. The significant D-peak contrast in the Raman map demonstrates that the quality of Co-etched edges is much higher than edges produced by conventional lithography/plasma etching method.

    3. Small-Sized Carbon Nanohorns Enabling Cellular Uptake Control (pages 2524–2531)

      Minfang Zhang, Xin Zhou, Sumio Iijima and Masako Yudasaka

      Article first published online: 4 JUN 2012 | DOI: 10.1002/smll.201102595

      Thumbnail image of graphical abstract

      Graphene tubules with lengths about 20–50 nm are separated from aggregates of single-walled carbon nanohorns (SWNHs). This material exhibits superiority in cellular uptake control after functionalization. Small-sized SWNHs are almost completely inhibited in RAW 264.7 macrophages by attaching phospholipid polyethylene glycol (PL-PEG), and are selectively taken up by KB cells after folic acid (FA) functionalization.

    4. Prussian Blue Analogues of Reduced Dimensionality (pages 2532–2540)

      Régis Y. N. Gengler, Luminita M. Toma, Emilio Pardo, Francesc Lloret, Xiaoxing Ke, Gustaaf Van Tendeloo, Dimitrios Gournis and Petra Rudolf

      Article first published online: 3 JUL 2012 | DOI: 10.1002/smll.201200517

      Thumbnail image of graphical abstract

      Controlled fabrication of Prussian Blue analogues by means of a modified Langmuir–Schaefer technique, where the organometallic magnets are synthesized from precursors in a self-limited reaction on a clay mineral surface, is demonstrated. For magnetic ordering a high Tc of ~80 K is preserved in this low dimensionality assembly. However, the “on surface” synthesis influences the morphology of the product and thereby creates interesting new properties.

    5. A Dual Gradient Assay for the Parametric Analysis of Cell–Surface Interactions (pages 2541–2547)

      Paul M. Reynolds, Rasmus H. Pedersen, Mathis O. Riehle and Nikolaj Gadegaard

      Article first published online: 8 JUN 2012 | DOI: 10.1002/smll.201200235

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      Orthogonal topographical gradients of varying pitch and depth are fabricated by sacrificial etching of a deposited mask. This continuous gradient of groove depth, spanning three orders of magnitude, facilitates the high-throughput screening of cellular response. Cell specific response is observed for three different cell lines to the combinations of groove pitch and depth, paving the way for future biomedical device design.

    6. Highly Ordered Arrays of Particle-in-Bowl Plasmonic Nanostructures for Surface-Enhanced Raman Scattering (pages 2548–2554)

      Xianglin Li, Yongzhe Zhang, Ze Xiang Shen and Hong Jin Fan

      Article first published online: 6 JUN 2012 | DOI: 10.1002/smll.201200576

      Thumbnail image of graphical abstract

      A new plasmonic particle-in-bowl array is fabricated based on nanosphere self-assembly (NSL) and atomic layer deposition (ALD). The strong electric field at the ALD Al2O3 gap separating the Ag particle from the Au bowl is revealed by numerical simulation and demonstrated by surface-enhanced Raman scattering (SERS) measurements; both show that the field enhancement is strongly dependent on the Ag particle size and gap distance.

    7. Characterization of Mass and Swelling of Hydrogel Microstructures using MEMS Resonant Mass Sensor Arrays (pages 2555–2562)

      Larry J. Millet, Elise A. Corbin, Robert Free, Kidong Park, Hyunjoon Kong, William P. King and Rashid Bashir

      Article first published online: 11 JUN 2012 | DOI: 10.1002/smll.201200470

      Thumbnail image of graphical abstract

      Micrometer-scale hydrogel structures fabricated onto MEMS resonant mass sensors enable the measurement of hydrogel mass for materials characterization. The size of the hydrogel microstructures and the density of hydrogel immersion media influence the measured mass. The results suggest that MEMS sensor readings reflect the completeness of hydrogel swelling and hydrodynamic loading on hydrogel microstructures.

    8. Influence of the Molecular Structure and Morphology of Self-Assembled 1,3,5-Benzenetrisamide Nanofibers on their Mechanical Properties (pages 2563–2570)

      Daniel Kluge, Julia C. Singer, Jens W. Neubauer, Frank Abraham, Hans-Werner Schmidt and Andreas Fery

      Article first published online: 23 MAY 2012 | DOI: 10.1002/smll.201200259

      Thumbnail image of graphical abstract

      The mechanical properties of supramolecular nanofibers are revealed by means of nanomechanical bending tests. Different molecular structures have a strong influence on the diameter and stiffness of the fibers. In contrast, the Young's modulus is surprisingly little affected by differences in the chemical structure.

    9. Measuring True Young's Modulus of a Cantilevered Nanowire: Effect of Clamping on Resonance Frequency (pages 2571–2576)

      Qingquan Qin, Feng Xu, Yongqing Cao, Paul I. Ro and Yong Zhu

      Article first published online: 23 MAY 2012 | DOI: 10.1002/smll.201200314

      Thumbnail image of graphical abstract

      The effect of clamping on resonance frequency and thus measured Young's modulus of nanowires (NWs) is systematically investigated via a combined experimental and simulation approach. The resonance frequency increases with the increasing clamp size until approaching that under the “fixed” boundary condition. The critical clamp size is identified as a function of NW diameter and NW Young's modulus. Design guidelines on the critical clamp size are provided.

    10. Mechanism of Cellular Uptake of Graphene Oxide Studied by Surface-Enhanced Raman Spectroscopy (pages 2577–2584)

      Jie Huang, Cheng Zong, He Shen, Min Liu, Biao Chen, Bin Ren and Zhijun Zhang

      Article first published online: 29 MAY 2012 | DOI: 10.1002/smll.201102743

      Thumbnail image of graphical abstract

      Surface-enhanced Raman scattering (SERS) spectroscopy reveals that graphene oxide (GO) loaded with Au nanoparticles is inhomogeneously distributed inside Ca Ski cells. The cell entry of the Au-GO is mainly through clathrin-mediated, energy-dependent endocytosis.

    11. Surface Functionalization of Nanoparticles to Control Cell Interactions and Drug Release (pages 2585–2594)

      Rongcong Luo, Björn Neu and Subbu S. Venkatraman

      Article first published online: 6 JUN 2012 | DOI: 10.1002/smll.201200398

      Thumbnail image of graphical abstract

      The surface of poly(dl-lactide-co- glycolide) nanoparticles is modified with multilayer polyelectrolytes via layer-by-layer deposition. Drug release from the nanoparticles is tunable by adjusting the architecture of the coated layers. The outermost layer characteristics affect cell–particle interaction. Particles with a positively charged outermost layer have higher cellular uptake efficiency.

    12. Patterning of Crystalline Organic Materials by Electro-hydrodynamic Lithography (pages 2595–2601)

      Pola Goldberg-Oppenheimer, Peter Kohn, Richard M. Langford and Ullrich Steiner

      Article first published online: 4 JUN 2012 | DOI: 10.1002/smll.201200194

      Thumbnail image of graphical abstract

      Organic crystalline materials are patterned on the micrometer length scale using the electro-hydrodynamic lithography technique. Crystal alignment with respect to the electric field lines within these structures is facilitated by micrometer-sized meso-structures, accelerating crystal alignment compared to unstructured films.

    13. A Controllable Chiral Molecular Machine: Movement on Molecular Level (pages 2602–2607)

      Wenlong Yang, Yongjun Li, Jianhong Zhang, Nan Chen, Songhua Chen, Huibiao Liu and Yuliang Li

      Article first published online: 4 JUN 2012 | DOI: 10.1002/smll.201200670

      Thumbnail image of graphical abstract

      The intensity of circular dichroism (CD) signals is dependent on the dihedral angles of binaphthalene rings, which can be modulated through introducing tunable units into two naphthalene groups. As a result, the movement of the macrocycle DB24C8 along the thread driven by pH can influence the dihedral angle between the two naphthalene rings, thus modulating the CD signals.

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