The Molecular Density of States in Bacterial Nanowires
Mohamed Y El-Naggar 1*, Yuri A Gorby 2, Wei Xia 3 and Kenneth H Nealson 1
1 University of Southern California
2 J. Craig Venter Institute
3 Veeco Metrology, Inc.
* To whom correspondence should be addressed. E-mail: mnaggar{at}usc.edu.
Submitted on March 28, 2008
Revised on April 3, 2008
Accepted on 8 April 2008
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Abstract |
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The recent discovery of electrically conductive bacterial appendages has significant physiological, ecological, and biotechnological implications, but the mechanism of electron transport in these nanostructures remains unclear. We here report quantitative measurements of transport across bacterial nanowires produced by the dissimilatory metal-reducing bac-terium (DMRB), Shewanella oneidensis MR-1, whose electron transport system is being investigated for renewable energy recovery in microbial fuel cells and bioremediation of heavy metals and radionuclides. The Shewanella nanowires display a surprising non-linear electrical transport behavior, where the voltage dependence of the conductance reveals peaks indicat-ing discrete energy levels with higher electronic density of states. Our results indicate that the molecular constituents along the Shewanella nanowires possess an intricate electronic structure that plays a role in mediating transport.
Key Words:
Bacterial Nanowires, Cell Biophysics, Electron Transport, Metal-reducing Bacteria, Molecular Conductance, Scanning Probe Microscopy
