Biofilm Activity of Shewanella oneidensis on Gold Electrodes Monitored by Electrochemical Surface Plasmon Resonance Imaging (eSPRi)

This study investigates the use of electrochemical surface plasmon resonance imaging (eSPRi) to monitor the growth and activity of Shewanella oneidensis biofilms on gold film electrodes. Motivated by the need to understand extracellular electron transfer (EET) in biofilms, particularly the roles of surface-attached and soluble redox-active molecules, we aimed to correlate eSPRi data with electrochemical measurements during biofilm development. The combined measurements revealed distinct phases of biofilm behavior, including an initial period in which current and eSPRi signal increased together, followed by later phases in which current declined while the eSPRi signal remained elevated or increased. These findings highlight the complexity of biofilm-electrode interactions and demonstrate the value of eSPRi as a complementary tool for studying microbial electrochemical interfaces. Ultimately, this work paves the way for more nuanced explorations of microbial–electrode interfaces, with potential payoffs in the optimization of bioelectrochemical technologies.