Although several studies have focused on using electrochemical methods to prevent bacteria attachment or promote inactivation, the mechanisms for bacteria inactivation at low applied potentials is unclear. To address this issue, we assessed the bacteria cell inactivation mechanisms while applying low anodic and cathodic potentials to electrode surfaces. Several mechanisms have been proposed to be responsible for bacteria inactivation, including: 1) electroporation, 2) disruption of the intracellular redox homeostasis by the applied electric field, which caused cellular reactive oxygen species (ROS) generation, 3) direct electron transfer reactions, 4) acidic/basic pH generation at the electrode surface, and 7) ROS generation at the electrode surface. We study the attachment and inactivation of a model biofilm forming bacteria (i.e., <i>Pseudomonas aeruginosa</i>) at boron-doped diamond (BDD) electrode surfaces at applied potentials ranging from -0.2 V to 1 V (vs Ag/AgCl). Scanning electrochemical microscopy was utilized to characterize the formation of ROS species and the near surface pH resulting from electrochemical reactions. The experimental results were interpreted by reactive mass transport modeling and insights were used to propose inactivation mechanisms as a function of electrode potential.<br/>

Mechanisms of bacteria inactivation at low applied potentials

2019 Spring National Meeting

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