Electron Transfer between the Gram-Positive Enterococcus faecalis Bacterium and Electrode Surface through Osmium Redox Polymers

The interaction between microorganisms that contain thick cell walls, such as the Gram-positive bacterium Enterococcus faecalis, and conductive surfaces can be improved by using redox polymers as mediators. Herein, we report a detailed electrochemical characterization of the communication between E. faecalis cells and a series of osmium redox polymers with different redox potentials. The current generated from glucose oxidation by films containing osmium redox polymers and E. faecalis cells increase over time (28 h), owing to a decrease in charge-transfer resistance within the films, possibly owing to improved penetration of the redox polymer within the bacterial cell wall.