The Role of Near Electrode Solution Chemistry on Bacteria Attachment and Poration at Low Applied Potentials

This research investigated mechanisms for biofouling control at boron-doped diamond (BDD) electrode surfaces polarized at low applied potentials (e.g., -0.2 to 1 V versus Ag/AgCl), using Pseudomonas aeruginosa as a model organism. Results indicated that electrostatic interactions between bacteria and ionic electrode functional groups facilitated bacteria attachment at the open circuit potential (OCP). However, under polarization the applied potential governed these electrostatic interactions and electrochemical reactions resulted in surface bubble formation and near-surface pH modulation that decreased surface attachment under anodic conditions. The poration of the attached bacteria occurred at OCP conditions and increased with the applied potential. Scanning electrochemical microscopy (SECM) provided near-surface pH and oxidant formation measurements under anodic and cathodic polarizations. The near-surface pH was 3.1 at 1.0 V vs. Ag/AgCl and 8.0 at -0.2 V vs. Ag/AgCl and was possibly a contributor to ba...