The Regents of the University of California, Irvine Irvine United States
Electronic transport is conventionally the domain of man-made materials and devices, but anaerobic respiration by some sediment microbes requires shuttling electrons from the cell to remote electron acceptors. The model bacterium Geobacter sulfurreducens produces electrically conductive, protein fiber appendages, representing a new class of materials with between the protein building blocks of these assemblies and the canonical building blocks of inorganic and organic conductors and semiconductors, it is clear that Nature has developed its own design principles for long-range electronic conducting systems. The biomolecular identity and supramolecular order underpinning biological conductive materials are poorly understood, as are the mechanisms by which these structures support electron transport. This report summarizes research in the Hochbaum lab funded by the AFOSR YIP on the characterization of charge transport mechanisms and structure property relationships in conductive protein nanowires. These efforts establish distinctive biomolecular design principles for long-range electron transport in self-assembling peptide nanofibers and native bacterial appendages. Such materials serve as an experimental platform to understand long-range charge transport in biological materials in general, and as promising technological platforms for bioelectronic interfaces.