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Distance dependence in peptide-mediated long range electron transfer

Joanna Juhaniewicz ,  Slawomir Sek 

Warsaw Uniwersity, Department of Chemistry, Pasteura 1, Warsaw 02-093, Poland

Abstract

We present the peptide molecules which act as a mediator for long range electron transfer. Understanding the role of peptides in bridge-mediated tunneling of electrons is essential from biological point of view but is also very important for the development of biosensors and nanotechnology. Investigation of electrical properties of single molecules is of special interest because of their potential application in molecular electronics. In some cases we observed the current rectification.

We designed and synthesized 4 thiolated peptide derivatives containing from 1 to 4 proline residues and used them for preparation of self-assembled monolayers (SAMs) on gold electrodes. The quality of the resulting layers and the SAMs coverage were examined using electrochemical impedance spectroscopy and cyclic voltammetry. The electrical behavior of gold-molecule-gold junctions incorporating these peptides was investigated using scanning tunneling spectroscopy (STS). The STS method allows to measure the conductance of a single molecule entrapped in a molecular junction. It also provides the information about the influence of the length and the secondary structure of the molecule on electron transfer efficiency. 

prolina1_4.jpg

Fig.1 Structure of the synthesized peptide consisting of L-proline and L-cysteine with protected thiol and amine groups and a cystamine linker.

 

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Related papers

Presentation: Poster at SMCBS'2009 International Workshop, by Joanna Juhaniewicz
See On-line Journal of SMCBS'2009 International Workshop

Submitted: 2009-08-26 16:54
Revised:   2009-08-27 14:13