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Spectroscopy
Volume 24 (2010), Issue 1-2, Pages 173-176
http://dx.doi.org/10.3233/SPE-2010-0425

Cytochrome C as a benchmark system for a two-layer gold surface with improved surface-enhancement for spectro-electrochemistry

Christoph Nowak,1,2 Denise Schach,1,2 Marc Grosserüschkamp,1,2 Wolfgang Knoll,2 and Renate L.C. Naumann1,2,3

1Max Planck Institute for Polymer Research, Mainz, Germany
2Austrian Institute of Technology GmbH–ARC, Vienna, Austria
3Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz-55128, Germany

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A two-layer gold surface is developed for use with electrochemistry followed by surface-enhanced infrared absorption spectroscopy (SEIRAS) consisting of a conducting underlayer onto which Au nanoparticles (AuNPs) are grown by self-catalyzed electroless deposition. AuNPs are grown on protruding substructures of the 25 nm thin underlayer. The enhancement factor of the two-layer gold surface is controlled by the growth conditions. Cytochrome c adsorbed to a self-assembled monolayer of mercaptoethanol is used as a benchmark system for the investigation of complex heme proteins from the respiratory chain such as cytochrome c oxidase and the bc1 complex. Under optimum conditions the absorbance of the amide I band of cytochrome c is increased by a factor of 5 vs. classical SEIRAS surface. Reversible reduction/oxidation of cytochrome c on the two-layer gold surface is shown to take place by cyclic voltammetry.