Effects of Bio-Au Nanoparticles on Electrochemical Activity of Shewanella oneidensis Wild Type and ΔomcA/mtrC Mutant

Both Shewanella oneidensis MR-1 wild type and its mutant Delta omcA/mtrC are capable of transforming Au-III into Au nanoparticles (AuNPs). Cyclic voltammetry reveals a decrease in redox current after the wild type is exposed to Au-III but an increase in oxidation current for the mutant. The peak current of the wild type is much higher than that of the mutant before the exposure of Au-III, but lower than that of the mutant after the formation of AuNPs. This suggests that damage to the electron transfer chain in the mutant could be repaired by AuNPs to a certain extent. Spectroscopy and SDS-PAGE analysis indicate a decrease in cell protein content after the formation of AuNPs, which provides a convenient way to detect intracellular information on cells.