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Gold Film (gold + film)

Distribution by Scientific Domains
Chemistry36%
Physics and Astronomy27%

Selected Abstracts

The Anomalous Infrared Transmission of Gold Films on Two-Dimensional Colloidal Crystals,

ADVANCED MATERIALS, Issue 12 2006
P. Zhan
Plasmonic crystals with submicrometer periodicity and extraordinary dispersion properties that depend on the polarization of incident light are obtained by partially covering silica or polystyrene spheres with a thin gold film (see figure). The optical properties of these two-dimensional ordered metallodielectric microstructures shown here promise a wide range of potential near-infrared applications. [source]

Comparison of Electrochemical and Surface Plasmon Resonance Immunosensor Responses on Single Thin Film

ELECTROANALYSIS, Issue 20 2008
Ryoji Kurita
Abstract This paper reports results obtained when comparing an electrochemical enzyme immunosensor and a surface plasmon resonance (SPR) based immunosensor on the same gold surface installed in an electrochemical SPR flow cell. Simultaneous electrochemical and SPR measurements were performed on a gold surface modified with multilayers of poly- L -lysine and poly-styrenesulfonate assembled with the layer-by-layer method. First, we obtained the SPR response induced by the formation of an immunocomplex from the shift in the SPR angle by injecting an anti tumor necrosis factor-, antibody solution labeled with alkaline phosphatase into the flow cell containing the multilayer modified with tumor necrosis factor-,. Then we compared this SPR result with that obtained for the electrochemical oxidation current of p -aminophenol catalyzed by alkaline phosphatase from p -aminophenolphosphate on the same gold film. We compared the two immunosensor responses obtained using the different measurement principles and found that there was a high correlation efficient of 0.973 between them. This was because we were able to immobilize the immunoreagents with good stability and without losing the transport of the enzyme product in the multilayer whose thickness we easily controlled with nanometer scale accuracy. We also report that the detection limit of our electrochemical immunosensor after optimization was around 100,pg/mL (0.4,pM), which is one of the lowest values yet reported for an electrochemical immunosensor. [source]

The Anomalous Infrared Transmission of Gold Films on Two-Dimensional Colloidal Crystals,

ADVANCED MATERIALS, Issue 12 2006
P. Zhan
Plasmonic crystals with submicrometer periodicity and extraordinary dispersion properties that depend on the polarization of incident light are obtained by partially covering silica or polystyrene spheres with a thin gold film (see figure). The optical properties of these two-dimensional ordered metallodielectric microstructures shown here promise a wide range of potential near-infrared applications. [source]

Coherent acoustic phonons in a thin gold film probed by femtosecond surface plasmon resonance

JOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2008
Shoichi Yamaguchi
Abstract We report on coherent phonon detection in a thin gold film by a new femtosecond pump-probe surface plasmon resonance (SPR) technique. Acoustic coherent phonons are generated impulsively in the gold film on a prism, and they are detected in the time domain through the reflectivity modulation for probe pulses that satisfy the SPR condition. We observed not only the fundamental vibration of a longitudinal acoustic phonon but also the overtones up to the fourth. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Voltage-induced morphological modifications in oocyte membranes containing exogenous K+ channels studied by electrochemical scanning force microscopy

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2008
Andrea Alessandrini
Abstract We report on a novel use of electrochemical scanning force microscopy (SFM) for the investigation of morphological modifications occurring in plasma membranes containing voltage-gated ion channels, on membrane potential variation. Membrane patches of Xenopus laevis oocytes microinjected with exogenous KAT1 cRNA, deposited by a stripping method at the surface of a derivatized gold film in inside-out configuration, have been imaged by SFM in an electrochemical cell. A potentiostat was used to maintain a desired potential drop across the membrane. Performing imaging at potential values corresponding to open (,120 mV) and closed (+20 mV) states for KAT1, morphological differences in localized sample zones were observed. Particularly, cross-shaped features involving a significant membrane portion appear around putative channel locations. The reported approach constitutes the first demonstration of an SPM-based experimental technique suitable to investigate the rearrangements occurring to the plasma membrane containing voltage-gated channels on transmembrane potential variation. Microsc. Res. Tech., 2008. © 2007 Wiley-Liss, Inc. [source]

Cover Picture: Biotechnology Journal 11/2009

BIOTECHNOLOGY JOURNAL, Issue 11 2009
Article first published online: 13 NOV 200
Cover illustration: Focus on Biochips. The cover image for this Special Issue edited by Hyun Gyu Park shows a simulation of a thin gold film perforated with periodic nanopores. This setup has unique optical properties suitable for detecting thin layers of biomolecules , in this case a suspended lipid bilayer incorporating transmembrane proteins. See the article by Maynard et al. on p. 1542 of this issue (http://dx.doi.org/10.1002/biot.200900195). [source]

Plasmonic modes of gold nano-particle arrays on thin gold films

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 10 2010
A. Hohenau
Abstract Regular arrays of metal nanoparticles on metal films have tuneable optical resonances that can be applied for surface enhanced Raman scattering or biosensing. With the aim of developing more surface selective geometries we investigate regular gold nanoparticle arrays on 25 nm thick gold films, which allow to excite asymmetric surface plasmon modes featuring a much better field confinement compared to the symmetric modes used in conventional surface plasmon resonance setups. By optical extinction spectroscopy we identify the plasmonic modes sustained by our structures. Furthermore, the role of thermal treatment of the metal structures is investigated, revealing the role of modifications in the crystalline structure of gold on the optical properties. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Ellipsometry study of ultra thin layers of evaporated gold

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2008
Alexei Nabok
Abstract Optical properties of ultra thin (from 1 to 40 nm) films of gold evaporated on glass and silicon were studied with the method of spectroscopic ellipsometry in both external and internal reflection configurations as well as with the UV-visible absorption spectroscopy. The results obtained showed a gradual shift of the plasmon peak from 580 nm for 1 nm thick films to more than 1000 nm for thick (40 nm) gold films. Such phenomenon can be interpreted in terms of quantum confinement of surface plasmons in gold islands. The threshold of the metal-dielectric transition was found at the film thickness between 4 and 5 nm. Thiolation of the surface of glass has resulted in a slight decrease in the effective thickness of gold layer and respective smaller blue shift of n (,) and k (,) dispersion curves, however no dramatic changes were observed in the film morphology. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]