News from the micro-nano world

Download News from the micro-nano world

Post on 06-Jul-2016




4 download

Embed Size (px)


<ul><li><p>Devices and applications</p><p>Cool Fuel Cell</p><p>A research group from the applied-</p><p>physics department at the Universidad</p><p>Complutense de Madrid (Spain) have</p><p>developed a new electrolyte for solid-</p><p>oxide fuel cells, which operates at</p><p>temperatures hundreds of degrees lower</p><p>than those of conventional electrolytes,</p><p>which could help make such fuel cells</p><p>more practical. Jacobo Santamaria</p><p>and his colleagues modified a yttria-</p><p>stabilized zirconia electrolyte, a com-</p><p>mon type of electrolyte in solid-oxide</p><p>fuel cells, so that it works at just above</p><p>room temperature. Combined with</p><p>improvements to the fuel-cell elec-</p><p>trodes, this could lower the temperature</p><p>at which these fuel cells operate. Draw-</p><p>photon. Further information is available</p><p>news from the micro-nano world DOI: 10.1002/smll.200801187</p><p>1268of the on earlier work by other researchers,</p><p>Santamaria found that the ionic con-</p><p>ductivity at low temperatures could be</p><p>greatly improved by combining layers of</p><p>the standard electrolyte materials with</p><p>10-nm-thick layers of strontium titanate.</p><p>He found that, because of the differ-</p><p>ences in the crystal structures (Figure 1)</p><p>of the materials, a large number of</p><p>oxygen vacancies form where these two</p><p>materials meet. These vacancies form</p><p>pathways that allow the oxygen ions to</p><p>move through the material, improving</p><p>the conductivity of thematerials at room</p><p>temperature by a factor of 100 million.</p><p>Figure 1. Scanning transmission electron</p><p>micrcoscopy image shows the crystal structure 2008 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weat: &amp;</p><p>&amp;langenple of quantum information transfer</p><p>from a single electron to a singleFunding</p><p>Quantum-Transport Research</p><p>Leo Kouwenhoven of the Kavli</p><p>Institute of Nanoscience at TU Delft</p><p>(The Netherlands) is one of the European</p><p>researchers to have been awarded a</p><p>European Research Council (ERC)</p><p>Advanced Grant. The ERC Advanced</p><p>Grant is a subsidy from the ERC for</p><p>experienced scientists who carry out</p><p>innovative, pioneering research. Kouwen-</p><p>hoven is expected to receive s1.8M overa period of five years to further develop</p><p>his research in the field of quantum</p><p>optoelectronics. Kouwenhoven will spend</p><p>the money on new measuring equipment</p><p>and the appointment of PhD candidates.</p><p>With the aid of theERC funds he hopes to</p><p>demonstrate within five years the princi-tee. For further information, please visit:</p><p>www.nanotech. netFor further information, please visit:</p><p></p><p>21163/?nlid1250</p><p>Upcoming events</p><p>Nanotech Northern Europe</p><p>The Nanotech Northern Europe</p><p>2008 takes place from 2325 September</p><p>in Bella Centre, Copenhagen (Denmark).</p><p>The event is intended to be a place for the</p><p>global nanotechnology community to</p><p>meet, collaborate, and do business. Due</p><p>to the fact that nanotechnology encom-</p><p>passes a huge range of technologies, at</p><p>differing stages of development, the event</p><p>not only features excellent research work</p><p>but also enables companies to convey</p><p>their visions for the market impact of</p><p>nanotechnology or to demonstrate their</p><p>commercial products in the fully inte-</p><p>grated exhibition. FlemmingBesenbacher,</p><p>member of the Small Editorial Board, is</p><p>Co-chairman of the Programme Commit-inheim small 2008, 4, No. 9, 12681269</p></li><li><p>Properties andcharacterization</p><p>Intriguing Structures of GoldNanoparticles</p><p>Scientists from Germany, Canada,</p><p>and The Netherlands have studied tiny</p><p>gold nanoparticles and found them to</p><p>have fascinating arrangements of their</p><p>constituent atoms. For example, twenty</p><p>gold atoms form a tetrahedron. The</p><p>nineteen-atom cluster (Figure 2) is a</p><p>truncated pyramid, which can be formed</p><p>by cutting off one corner atom from the</p><p>twenty-atom gold pyramid. The structures</p><p>have been identified using the free-</p><p>electron laser for infrared experiments</p><p>(FELIX) at the FOM Institute for Plasma</p><p>Physics Rijnhuizen in Nieuwegein.</p><p>[1] T. Polcar, T. Kubart, E. Malainho, M. Vasi-</p><p>levskiy, N. M. G. Parreira, A. Cavaleiro,</p><p>Nanotechnology 2008, 19, 395202.</p><p>Health issues</p><p>Labeling of Enveloped Viruses</p><p>Anew study reports a generalmethod</p><p>of labeling enveloped viruses with semi-</p><p>conductor quantum dots (QDs) for use in</p><p>single-virus-trafficking studies. Retro-</p><p>viruses, including human immunodefi-</p><p>ciency virus (HIV), were successfully</p><p>tagged with QDs through the membrane</p><p>studies monitoring HIV particles using</p><p>QD labeling showed that a single virion</p><p>on the surface of target cells expressing</p><p>either CD4/CCR5 or DC-SIGN can be</p><p>detected. Further internalization studies</p><p>of QD HIV evidently showed that the</p><p>clathrin pathway is the major route for</p><p>DC-SIGN-mediated uptake of viruses.</p><p>According to the authors, the data</p><p>reported demonstrate the potential of</p><p>this QD labeling for visualizing the</p><p>dynamic interactions between viruses</p><p>and target cell structures.</p><p>[1] K.-I. Joo, Y. Lei, C.-L. Lee, J. Lo, J. Xie, S. F.</p><p>Hamm-Alvarez, Pin Wang, ACS Nano 2008,DOI: 10.1021/nn8002136.</p><p>Figure 3. General strategy for the site-specifiFigure 2. Structures of neutral gold nanopar-</p><p>ticles with seven, nineteen, and twenty atoms.Synthetic procedures</p><p>Nanoscale Color Control</p><p>A European research team has</p><p>reported a new design of decorative</p><p>tungsten oxide coatings. The coatings</p><p>were deposited with a graded refractive</p><p>index by magnetron sputtering from aDetailed knowledge about the geometries</p><p>of these nanoparticles is expected to lead</p><p>to a better understanding of the unex-</p><p>pected catalytic activity of very small gold</p><p>particles. Further information is available</p><p>at: artikel.</p><p>pag?objectnumber79098small 2008, 4, No. 9, 12681269tungsten target and pulsing the reactive</p><p>gas. The controlled injection of the</p><p>reactive gas can produce a concentration</p><p>profile gradient from pure tungsten to</p><p>tungsten trioxide, determining the final</p><p>apparent color of the coating. A dynamic</p><p>sputteringmodel was built to simulate the</p><p>growth of the coating during the reactive-</p><p>gas pulsing, which was validated by direct</p><p>measurement of the gradient of the</p><p>oxygen content in the deposited coatings.</p><p>Finally, these results were used for an</p><p>opticalmodel allowing the optical proper-</p><p>ties of the deposited tungsten oxide layer</p><p>to be described, again validated by</p><p>experimental analysis. According to the</p><p>authors, this procedure allows the deposi-</p><p>tion of coatings with the desired color by</p><p>using the models to finding the optimal</p><p>oxygen pulse parameters and the pro-</p><p>posed method can be easily applied to</p><p>almost any metalmetal oxide system. 2008 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinincorporation of a short acceptor peptide</p><p>(AP) that is susceptible to site-specific</p><p>biotinylation and attachment of strept-</p><p>avidin-conjugated QDs (Figure 3). The</p><p>researchers from the University of</p><p>Southern California (US) further found</p><p>that this AP-tag-based QD labeling had</p><p>little effect on the viral infectivity and</p><p>allowed for the study of the kinetics of the</p><p>internalization of the recombinant lenti-</p><p>virus enveloped with vesicular stomatitis</p><p>virus glycoprotein (VSVG) into the early</p><p>endosomes. It also allowed for the live</p><p>cell imaging of the trafficking of labeled</p><p>virus to the Rab5 endosomal compart-ments. Additionally, this study demon-</p><p>strated by direct visualization of a QD-</p><p>labeled virus that VSVG-pseudotyped</p><p>lentivirus enters cells independent of</p><p>clatherin and caveolin pathways, while</p><p>the entry of VSVG-pseudotyped retro-</p><p>virus occurs via the clathrin pathway. The</p><p>c labeling of enveloped viruses with QDs.heim 1269</p></li></ul>