Integrated nanocoating and biofilm engineering enhance extracellular electron transfer

Extracellular electron transfer (EET) at the cell-electrode interface is central to microbial electrochemical technologies. It remains constrained by the low conductivity of individual cells, physiological impairment associated with coating the cell surface with an interconnected, conductive polymer layer, and a limited capability for biofilm formation. Here, we develop a conductive, enhanced, and dynamic biohybrid system to overcome these barriers. We establish a recovery strategy for Shewanella oneidensis MR-1 cells coated with a conductive polydopamine (PDA) nanoshell, restoring cellular physiology while retaining the coating. The recovered cells exhibit enhanced EET and reduced charge-transfer resistance. We further promote biofilm formation in the recovered PDA-coated cells using a cyclic dimeric guanosine monophosphate (c-di-GMP)-targeted optogenetic approach. This integrated strategy generates a highly conductive, enhanced electrode biofilm with further improved EET and reduced charge-transfer resistance. This work highlights the importance of preserving cell physiology in the design of conductive biofilms and establishes a framework that integrates material coating with biofilm engineering for advanced bioelectronic interfaces.