Electrochemical monitoring of the Pseudomonas aeruginosa growth and the formation of a biofilm in TSB media.

Understanding and sensing microbial biofilm formation onto surfaces remains highly challenging for preventing corrosion and biofouling processes. For that purpose, we have thoroughly investigated biofilm formation onto glassy carbon electrode surfaces by using electrochemical technics. Pseudomonas aeruginosa was studied because of its remarkable ability to form biofilms in many environments. The modification of the electrode-solution interface during biofilm growth was monitored by in-situ measurement of the open-circuit potential and correlated with results obtained by electrochemical impedance spectroscopy, cyclic voltammetry, scanning electron microscopy and bioassays. The sensing of the biofilm formation hence suggests a multi-steps mechanism, which may include pre-formation of an insulating layer onto the surface prior to the bacteria adhesion and biofilm formation.

O-O bond cleavage via electrochemical reduction of a side-on peroxo dicopper model of hemocyanin.

The redox properties of the µ-η2:η2 peroxo complex [Cu2(H6M4h)(O2)]2+ were elucidated. This study constitutes the first full electrochemical and spectroelectrochemical characterization of a side-on peroxo Cu2:O2 bioinorganic model complex. The peroxo complex is irreversibly reduced in a two-electron process localized on the peroxo ligand triggering the cleavage of the O-O bond.