How bacteria use electric fields to reach surfaces

Area of Science:

• Microbiology
• Bioelectrochemistry
• Cellular Biophysics

Background:

• Electrotaxis, or directed cell movement in response to electric fields, is well-documented in eukaryotic cells.
• The ability of bacterial cells to exhibit electrotaxis and its role in biofilm formation remain largely unexplored.
• Distinguishing electric field effects from electrode polarization is crucial for studying microbial electrotaxis.

Purpose of the Study:

• To investigate whether bacterial cells can sense and respond to electric fields.
• To determine the role of electric fields in the formation of electroactive biofilms.
• To elucidate the mechanism underlying bacterial electrotaxis.

Main Methods:

• Development of a specialized experimental setup to form microbial electroactive biofilms.
• Differentiation between the direct effect of the electric field and the influence of the polarized electrode surface.
• Application of electric fields during the initial exposure of electrodes to bacterial inoculum.

Main Results:

• An electric field applied during inoculum exposure was essential for subsequent electroactive biofilm formation.
• Biofilm formation occurred similarly regardless of the electric field's direction.
• Bacterial cells likely detect K+ and Na+ ion gradients generated by the electric field at the electrode surface.

Conclusions:

• Bacterial cells possess the capability to sense electric fields, a phenomenon termed microbial electrotaxis.
• This microbial electrotaxis is a key factor in the formation of electroactive biofilms.
• The findings suggest potential implications for the biomedical field, particularly in controlling or utilizing biofilm formation.