Small

Cover image for Vol. 7 Issue 19

October 4, 2011

Volume 7, Issue 19

Pages 2677–2814

  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. Superparamagnetic Nanoparticles: N-Alkyl-PEI-Functionalized Iron Oxide Nanoclusters for Efficient siRNA Delivery (Small 19/2011) (page 2677)

      Gang Liu, Jin Xie, Fan Zhang, Zhiyong Wang, Kui Luo, Lei Zhu, Qimeng Quan, Gang Niu, Seulki Lee, Hua Ai and Xiaoyuan Chen

      Article first published online: 27 SEP 2011 | DOI: 10.1002/smll.201190069

      Thumbnail image of graphical abstract

      The cover illustrates a multifunctional gene delivery system interacting with cancer cells. Small interfering RNA (siRNA) is an emerging class of therapeutics, which works by regulating the expression of a specifi c gene involved in disease progression. Effective transport of siRNA with minimal side effects remains a challenge. In this study, a nonviral nanoparticle gene carrier was developed which contains a core of clustered superparamagnetic iron oxide nanoparticles and a shell of alkylated polyethyleneimine. This composite effectively binds siRNA with good protection, as demonstrated by an enzymatic degradation assay. Signifi cant down-regulation of luciferase by loaded nanocarriers was observed both in vitro and in vivo. In addition, transfected cells showed signifi cant MR imaging contrast compared to nontransfected ones. For more information, please read the Full paper “N-Alkyl-PEI-Functionalized Iron Oxide Nanoclusters for Effi cient siRNA Delivery” by H. Ai, X. Chen, and co-workers beginning on page 2742.

  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. Nanofluidic Chips: Real-Time Template-Assisted Manipulation of Nanoparticles in a Multilayer Nanofluidic Chip (Small 19/2011) (page 2678)

      H. Matthew Chen, Lin Pang, Michael S. Gordon and Yeshaiahu Fainman

      Article first published online: 27 SEP 2011 | DOI: 10.1002/smll.201190070

      Thumbnail image of graphical abstract

      The cover picture conceptualizes nanoparticles, quantum dots, or biomolecules being controlled in a multilayer, nanofl uidic chip architecture using electrokinetic forces to capture, hold, and release them by controlling the potential difference across the channels. The nanomaterials are delivered into the top microfl uidic channel and are captured onto the vertical nanochannels. Such dynamic control of the fl ow and placement of nanomaterials in a biocompatible, aqueous environment will have a profound impact on the fi elds of nanoplasmonics, nanophotonics, and medicine. With this architecture it is possible to capture and align nanoparticles into a 2D structure. For more information, please read the Full Paper “Real-Time Template-Assisted Manipulation of Nanoparticles in a Multilayer Nanofl uidic Chip” by L. Pang, Y. Fainman, and co-workers, beginning on page 2750.

  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 19/2011) (pages 2679–2684)

      Article first published online: 27 SEP 2011 | DOI: 10.1002/smll.201190071

  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. Formation Mechanisms of Uniform Nanocrystals via Hot-Injection and Heat-Up Methods (pages 2685–2702)

      Soon Gu Kwon and Taeghwan Hyeon

      Article first published online: 1 AUG 2011 | DOI: 10.1002/smll.201002022

      Thumbnail image of graphical abstract

      Synthesis of monodisperse nanocrystals is an important key to control physical and chemical properties on the nanoscale. Herein, two major synthetic methods for uniform nanocrystals, hot injection and heat-up, are reviewed. Mechanistic studies supported by theoretical background and simulation works show that both hot injection and heat-up have similar size distribution control mechanisms, namely, burst nucleation and diffusion-controlled growth.

  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. Photonic Devices: Sol–Gel Substrates with Engineered Multiple Photonic Bandgaps for Full-Color Photonic Devices (Small 19/2011) (page 2703)

      Seong Hwan Lee and Na Young Ha

      Article first published online: 27 SEP 2011 | DOI: 10.1002/smll.201190072

      Thumbnail image of graphical abstract

      The picture shows an inorganic glass fi lm with multiple photonic band gaps (MPBGs). The fi lm is fabricated by sol-gel processing of TiO2, SiO2, and mixed SiO2-TiO2 films. In the visible region, the spectral characteristics of MPBGs can be controlled by adjusting fabrication parameters. Using the film with engineered MPBGs, pixelated redgreenblue lasing emissions are achieved in a single sol-gel resonator with three kinds of dye-doped nematic liquid crystals. With easy fabrication via wet-processing, unique optical characteristics, and the advantages of an inorganic glass, the new sol-gel film is a functional substrate with enhanced optical performance for wide-band photonic applications such as refl ective displays, organic lasers, and organic light-emitting diodes.

  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. Sol–Gel Substrates with Engineered Multiple Photonic Bandgaps for Full-Color Photonic Devices (pages 2704–2708)

      Seong Hwan Lee and Na Young Ha

      Article first published online: 19 AUG 2011 | DOI: 10.1002/smll.201101083

      Thumbnail image of graphical abstract

      An inorganic glass film with engineered multiple photonic bandgaps (MPBGs) is fabricated by sol–gel processing. This sol–gel film consists of TiO2, SiO2, and mixed SiO2–TiO2 films and has controllable characteristics of MPBGs in the overall visible region. By using the sol–gel film as a resonator, a red–green–blue pixelated liquid-crystal laser is also demonstrated.

    2. Hydrogen Generation from Photocatalytic Silver|Zinc Oxide Nanowires: Towards Multifunctional Multisegmented Nanowire Devices (pages 2709–2713)

      A. Wouter Maijenburg, Eddy J. B. Rodijk, Michiel G. Maas, Monica Enculescu, Dave H. A. Blank and Johan E. ten Elshof

      Article first published online: 15 AUG 2011 | DOI: 10.1002/smll.201101198

      Thumbnail image of graphical abstract

      Photoactive nanowires: A novel photo-electrochemical nanowire diode that catalyzes the conversion of methanol and water to hydrogen under UV light is demonstrated. The wire consists of a metal and a metal oxide segment that are connected via a Schottky barrier. Other functions, such as remote- controlled autonomous movement, can be easily added to these wires in a modular fashion.

    3. Bi2WO6 Inverse Opals: Facile Fabrication and Efficient Visible-Light-Driven Photocatalytic and Photoelectrochemical Water-Splitting Activity (pages 2714–2720)

      Liwu Zhang, Clarissa Baumanis, Lars Robben, Tarek Kandiel and Detlef Bahnemann

      Article first published online: 22 AUG 2011 | DOI: 10.1002/smll.201101152

      Thumbnail image of graphical abstract

      The synthesis of Bi2WO6 inverse opal photonic crystals is performed via a facile and economical method. Bi2WO6 inverse opals exhibit much higher photocatalytic activities for the degradation of methylene blue and salicylicic acid under visible light illumination as compared with a reference nanofilm. The photon-to-hydrogen conversion efficiencies of photoelectrochemical water splitting exhibit an almost threefold increase due to the inverse-opal structure.

    4. Toroidal Micelles of Polystyrene-block-Poly(acrylic acid) (pages 2721–2726)

      Cuicui Liu, Gang Chen, Hang Sun, Jun Xu, Yuhua Feng, Zhou Zhang, Tom Wu and Hongyu Chen

      Article first published online: 17 AUG 2011 | DOI: 10.1002/smll.201100443

      Thumbnail image of graphical abstract

      A simple diblock copolymer, polystyrene-block-poly(acrylic acid), can be used to create toroidal micelles with and without inserted gold nanoparticles. Achievement of this elusive morphology at narrow ranges of DMF/H2O ratio can be attributed to an experimental setup that locks the solvent ratio while allowing sufficient time and kinetic energy for the polymer to evolve at high temperature.

  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. Mitochondria-Targeting Single-Walled Carbon Nanotubes for Cancer Photothermal Therapy (pages 2727–2735)

      Feifan Zhou, Shengnan Wu, Baoyan Wu, Wei R. Chen and Da Xing

      Article first published online: 22 AUG 2011 | DOI: 10.1002/smll.201100669

      Thumbnail image of graphical abstract

      Anovel therapy model with mitochondria- targeting single-walled carbon nanotubes (SWNTs), which convert laser energy into heat and selectively destroy the target mitochondria, is explored. The procedure induces cytochrome c release and cell apoptosis. The laser–SWNT method could be a promising selective local treatment modality, while minimizing adverse side effects.

    2. Resizing Metal-Coated Nanopores Using a Scanning Electron Microscope (pages 2736–2741)

      Guillaume A. T. Chansin, Jongin Hong, Jonathan Dusting, Andrew J. deMello, Tim Albrecht and Joshua B. Edel

      Article first published online: 24 AUG 2011 | DOI: 10.1002/smll.201101015

      Thumbnail image of graphical abstract

      Electron beam-induced shrinkage of metal-coated membrane nanopores for single-molecule fluorescence spectroscopy is achieved using only a scanning electron microscope. Shrinkage occurs on both the Al and Si3N4 sides, with carbon deposition being the dominant mechanism. The process is time-dependent and can be fine-tuned by optimizing the electron beam settings.

    3. N-Alkyl-PEI-Functionalized Iron Oxide Nanoclusters for Efficient siRNA Delivery (pages 2742–2749)

      Gang Liu, Jin Xie, Fan Zhang, Zhiyong Wang, Kui Luo, Lei Zhu, Qimeng Quan, Gang Niu, Seulki Lee, Hua Ai and Xiaoyuan Chen

      Article first published online: 22 AUG 2011 | DOI: 10.1002/smll.201100825

      Thumbnail image of graphical abstract

      Iron oxide nanoclusters (IOs) functionalized with alkylated polyethyleneimine of 2000 kDa molecular weight (Alkyl-PEI2k) are synthesized using Alkyl-PEI2k as the phase transfer material, which binds siRNA to form well-dispersed nanoparticles with uniform structure and narrow size distribution. With siRNA loading, Alkyl-PEI2k-IOs induce enhanced luciferase gene (fluc) silencing in fluc-4T1 cells in cell culture and in a fluc-4T1 tumor xenograft model with good biocompatibility.

      Corrected by:

      Corrigendum: Corrigendum: N-Alkyl-PEI-Functionalized Iron Oxide Nanoclusters for Efficient siRNA Delivery

      Vol. 7, Issue 23, 3260, Article first published online: 1 DEC 2011

    4. Real-Time Template-Assisted Manipulation of Nanoparticles in a Multilayer Nanofluidic Chip (pages 2750–2757)

      H. Matthew Chen, Lin Pang, Michael S. Gordon and Yeshaiahu Fainman

      Article first published online: 15 AUG 2011 | DOI: 10.1002/smll.201100264

      Thumbnail image of graphical abstract

      A multilayer nanophotonic, microfluidic, nanofluidic platform is demonstrated, in which nanoparticles are manipulated in real time by electrokinetic forces (via voltage potential) to form a nanoparticle structure above the underlying nanochannel membrane when an electric field is applied. Simulations of the nanoparticles' motion validate the approach, as confirmed by experiments in creating 200-nm nanoparticle 2D arrays.

    5. Use of a Chondroitin Sulfate Isomer as an Effective and Removable Dispersant of Single-Walled Carbon Nanotubes (pages 2758–2768)

      Liang Yu Yan, Weifeng Li, Sara Mesgari, Susanna S. J. Leong, Yuan Chen, Leslie S. Loo, Yuguang Mu and Mary B. Chan-Park

      Article first published online: 16 AUG 2011 | DOI: 10.1002/smll.201100708

      Thumbnail image of graphical abstract

      Three isomers of chondroitin sulfate (CS), i.e., CS-A, CS-B, and CS-C, are investigated as single-walled carbon nanotube (SWNT) dispersants in water. CS-C and CS-A, which have lower alpha-helix secondary structure contents, disperse the SWNTs much better than CS-B. The helical wrappings of CS-A and CS-C around the nanotubes was confirmed by atomic force microscopy and transmission electron microscopy.

    6. Fabrication of Silicon/Polymer Composite Nanopost Arrays and Their Sensing Applications (pages 2769–2774)

      Yunfeng Li, Junhu Zhang, Liping Fang, Tieqiang Wang, Shoujun Zhu, Yang Li, Zhanhua Wang, Liang Zhang, Liying Cui and Bai Yang

      Article first published online: 16 AUG 2011 | DOI: 10.1002/smll.201100313

      Thumbnail image of graphical abstract

      Composite nanopost arrays are fabricated by combining colloidal lithography and surface-initiated atom-transfer radical polymerization. Both the resultant nanoarchitecture and color of the composite nanopost arrays can be precisely tuned by adjusting the time of polymerization. The final composite nanopost arrays can be used as highly stable and repeatable sensors to rapidly detect water vapor.

    7. Antioxidant Deactivation on Graphenic Nanocarbon Surfaces (pages 2775–2785)

      Xinyuan Liu, Sujat Sen, Jingyu Liu, Indrek Kulaots, David Geohegan, Agnes Kane, Alex A. Puretzky, Christopher M. Rouleau, Karren L. More, G. Tayhas R. Palmore and Robert H. Hurt

      Article first published online: 5 AUG 2011 | DOI: 10.1002/smll.201100651

      Thumbnail image of graphical abstract

      Oxygen reacts with active sites on graphenic carbon surfaces to produce surface-bound oxygen intermediates that react heterogeneously with the antioxidant glutathione to restore the carbon surface and complete a catalytic cycle. This catalytic reaction is seen for a wide range of graphenic carbon materials and may contribute to oxidative stress pathways in nanotoxicity.

    8. Tumor-Targeted Polydiacetylene Micelles for In Vivo Imaging and Drug Delivery (pages 2786–2792)

      Nicolas Mackiewicz, Edmond Gravel, Anikitos Garofalakis, Julien Ogier, Jubi John, Daniel Miotto Dupont, Karine Gombert, Bertrand Tavitian, Eric Doris and Frédéric Ducongé

      Article first published online: 12 AUG 2011 | DOI: 10.1002/smll.201100212

      Thumbnail image of graphical abstract

      In vivo tumor targeting and drug delivery properties of small polymerized polydiacetylene (PDA) micelles (∼10 nm) is investigated in a murine MDA-MB-231 xenograft model of breast cancer. Uptake of (2000 Da poly(ethylene glycol))–PDA micelles in tumors is confirmed by co-localization with [18F]-fluorodeoxyglucose positron emission tomography and the tumor growth was significantly decreased when mice are treated with micelles loaded with paclitaxel.

    9. Probing the Nanoscale Phase Separation and Photophysics Properties of Low-Bandgap Polymer:Fullerene Blend Film by Near-Field Spectroscopic Mapping (pages 2793–2800)

      Xiao Wang, Hamed Azimi, Hans-Georg Mack, Mauro Morana, Hans-Joachim Egelhaaf, Alfred J. Meixner and Dai Zhang

      Article first published online: 18 AUG 2011 | DOI: 10.1002/smll.201101000

      Thumbnail image of graphical abstract

      Parabolic-mirror-assisted confocal far- field optical microscopy and high-resolution tip-enhanced near-field spectroscopic mapping are used to study the phase separation due to 1,8-octanedithiol (ODT) addition to a polymer:fullerene (PCPDTBT:PCBM) blend model system. The morphology, photoluminescence, Raman spectra, and nanoscale photophysics properties of the blend films with respect to the absence and presence of ODT are discussed.

    10. Effects of Water Molecules on Photoluminescence from Hierarchical Peptide Nanotubes and Water Probing Capability (pages 2801–2807)

      Minjie Wang, Shijie Xiong, Xinglong Wu and Paul K. Chu

      Article first published online: 16 AUG 2011 | DOI: 10.1002/smll.201100353

      Thumbnail image of graphical abstract

      Water molecule deficiency in the channel cores of bioinspired hierarchical peptide nanotubes not only modifies the bandgap of the subnanometer-scale crystalline structure formed by self-assembly, but also induces a characteristic ultraviolet photoluminescence peak, which is tunable and recoverable depending on incorporation or loss of water molecules.

    11. Targeted Delivery of Polyoxometalate Nanocomposites (pages 2808–2814)

      Georg Geisberger, Susann Paulus, Emina Besic Gyenge, Caroline Maake and Greta R. Patzke

      Article first published online: 23 AUG 2011 | DOI: 10.1002/smll.201101264

      Thumbnail image of graphical abstract

      The antiviral or anticancer properties of polyoxometalate (POM)/carboxymethyl chitosan (CMC) nanocapsules significantly reduce the cytotoxicity of bioactive POMs. They are used in a combined drug carrier-and-monitoring approach to track the unknown cellular pathways of POMs. Fluorescently labeled POM/CMC nanocomposites are detected in the perinuclear region of HeLa cells and nonlabeled nanospheres are tracked there with transmission electron microscopy.

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