Platinum disc electrode for in-situ electrochemical inactivation of bacterial growth in culture media

Abstract

We report electrochemical response of non-adherent E. coli cells on a platinum disc electrode and in-situ inactivation through electro-stimulation to reduce their growth. Anodic peak current in cyclic voltammetry (CV) was gradually enhanced with an increased cell density due to increase in redox protein riboflavin secreted by the viable bacterial cells. The presence of the bacterial cells showed capacitive nature of the electric double layer capacitance and reduced interfacial charge transfer resistance in impedance of Nyquist plot. Formation of bacterial layer on the electrode surface was also evident from the rise in both anodic peak current and potential with scan rate at fixed cell concentration. The electrochemical inactivation of bacterial cells showed significant reduction in colony formation and growth. The observed inhibitory response with electro-stimulation was in comparison with the inactivation of bacterial cells treated with UV irradiation and sonication. Negative bias potential as compare to positive or periodic bias potential has been more effective for inactivation of the viable bacterial cells in suspension.