Measurement of charge transfer during bacterial adhesion to an indium tin oxide surface in a parallel plate flow chamber

An experimental method is described for the measurement of charge transfer during bacterial adhesion in situ to a transparent, semiconducting indium t in oxide (ITO) coated glass plate in a parallel plate how chamber. Bacteria l adhesion is measured simultaneously with either the electric potential or the capacitance of the surface. Initial bacterial adhesion was accompanied by a change in electric potential of the surface with no measurable change in capacitance. Consequently, it can be assumed that the change in electri c potential of the surface is due to charge transfer between bacteria and t he surface, and it can be calculated that, on average, a charge of about 10 (-14) C per bacterium is exchanged during initial adhesion, which correspon ds to only several percent of the total surface charge of a bacterium. Char ge transfer could either be to or from the bacterial cell surface, dependen t on the bacterial strain involved and the ionic strength used. (C) 1999 El sevier Science B.V. All rights reserved.