title: An Electrochemical Strategy to Measure the Thickness of Electroactive Microbial Biofilms.
abstract: The study of electroactive microbial biofilms often requires knowledge of the biofilm thickness. Unfortunately, this parameter is, nowadays, only accessible through expensive microscopic techniques. This work overcomes this limitation by presenting a new strategy, exploiting the use of chronoamperometry (CA) alone. A mixed-culture biofilm is exposed to an O2-saturated solution during anode respiration to suppress its catalytic activity. Assuming that inactivation of the electrocatalytic process is caused by O2diffusion through the biofilm, a simple relation allows the use of the time constant extracted from the fitting of the curve of the CA trace during inactivation for the straightforward and quantitative determination of biofilm thickness. The biofilm thickness obtained with this method obeys the expected trend reported for biofilm growth and is in agreement with optical measurements. Contrary to the techniques usually employed to determine biofilm thickness, this new strategy is very rapid, nondisruptive, inexpensive, and may become a convenient alternative with respect to expensive and time-consuming microscopic techniques.
authors.affiliation: Department of Physics and Astronomy, VU University Amsterdam De Boelelaan 1081, 1081 HV, Amsterdam (The Netherlands) E-mail: d.millo@vu.nl.
authors.forename: Diego
authors.initials: D
authors.lastname: Millo
keywords: Geobacter sulfurreducens; bioelectrochemical systems; biofilm thickness; electrochemistry; oxygen