Effect of electric currents on bacterial detachment and inactivation

Abstract

Since biofilms show strong resistance to conventional disinfectants and antimicrobials, control of initial bacterial adhesion is generally accepted as one of the most effective strategies for preventing biofilm formation. Although electrical methods have been widely studied, the specific properties of cathodic, anodic, and block currents that influence the bacterial detachment and inactivation remained largely unclear. This study investigated the specific role of electric currents in the detachment and inactivation of bacteria adhered to an electrode surface. A real-time bacterial adhesion observation and control system was employed that consisted of Pseudomonas aeruginosa PAO1 (PAO1) with green fluorescent protein as the indicator microorganism and a flow cell reactor mounted on a fluorescent microscope. The results suggest that the bacteria that remained on the electrode surface after application of a cathodic current were alive, although the extent of detachment was significant. In contrast, when an anodic current was applied, the bacteria that remained on the surface became inactive with time, although bacterial detachment was not significant. Further, under these conditions, active bacterial motions were observed, which weakened the binding between the electrode surface and bacteria. This phenomenon of bacterial motion on the surface can be used to maximize bacterial detachment by manipulation of the shear rate. These findings specific for each application of a cathodic or anodic electric current could successfully explain the effectiveness of block current application in controlling bacterial adhesion.

Semiquantitative Performance and Mechanism Evaluation of Carbon Nanomaterials as Cathode Coatings for Microbial Fouling Reduction

“…With regard to the electrochemical mechanism of biofouling reduction, the influence of an electric current or potential on bacterial adhesion (12), detachment (10,(13)(14)(15), and inactivation (15)(16)(17) has been widely examined. The most commonly accepted theories are that the cathode repels bacteria via electrostatic interactions and the anode inactivates bacteria through direct and indirect oxidation (4,18).…”

Aryl Rhodanines Specifically Inhibit Staphylococcal and Enterococcal Biofilm Formation

“…Polymer brush coatings are monolayer coatings of modified polymer chains that have been shown to prevent bacterial adhesion to coated surfaces (33)(34)(35). The application of low-intensity electrical currents to electrically conductive implants has also been shown to decrease bacterial colonization (16,22,(52)(53)(54)(55). Similarly, the application of low-energy surface acoustic waves to urinary catheters prevented bacterial colonization in an animal infection model (18).…”

Novel methods for debridement of dental implant surfaces contaminated by biofilm

“…116 As well, in a past study, Hong et al showed that a constant low current applied at a voltage well above the electrolysis threshold of water could remove up to 80% of the adherent biofilm from a conductive material after 20 minutes of treatment time. 120 The results from our study show a comparable reduction in biofilm activity, but using ultralow voltage and lower current, and in a shorter time.…”

“…113 A constant low current applied at a voltage well above the electrolysis threshold of water has been shown to remove up to 80% of the adherent biofilm from a conductive material after 20 minutes of treatment time. 120 It is also known that a low electrical current flow (1.5-10 mA) through titanium is able to enhance the antibacterial effects of chlorhexidine. 121 AlHashedi et al applied a current of 2.3 mA for 5 minutes at 1.8V and showed a reduction in bacterial viability and in the number of attached bacteria on an implant.…”