We have applied blocking electrochemical collisions to several previously unstudied bacteria strains in order to better understand how bacteria characteristics influence current transients produced during the experiments. Transients in the steady state oxidation current of ferrocenemethanol at an ultramicroelectrode (UME) were observed when individual bacteria collided with the electrode surface. As ferrocenemethanol is oxidized to ferrocenium methanol, the electric field at UME promotes migration of negatively charged bacteria to the electrode. Adsorption of bacteria to the UME inhibits ferrocenemethanol diffusion from the bulk solution, resulting in decreasing current transients having either blip or step shapes that vary reproducibly between bacteria types. By altering the concentration of the supporting electrolyte in solution, dependences of the frequency of collisions and transient characteristics were observed. At low electrolyte concentrations (100 µM KCl), blip transients were more abundant for some bacteria than at moderate electrolyte concentrations (1.0 mM KCl). However, at higher electrolyte concentration (5.0 mM KCl), the blip transients were no longer observed and were replaced with step transients. The mechanism of this effect is currently being investigated using fluorescence microscopy to correlate optical observations to transients in the current–time curves generated from blocking collision experiments.

Sensing of single bacteria using blocking electrochemical collisions and the dependence of current transients on supporting electrolyte concentration

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.