Visualization of Charge Transfer from Bacteria to a Self-doped Conjugated Polymer Electrode Surface Using Conductive Atomic Force Microscopy.

Abstract

In this work, we aim to provide a better understanding for the reasons behind electron transfer inefficiencies between electrogenic bacterium and the electrode in microbial fuel cells. We do so by using a self-doped conjugated polyelectrolyte (CPE) as the electrode surface, onto which Geobacter sulfurreducens is placed, then using conductive atomic force microscopy (C-AFM) to directly visualize and quantify the electrons that are transferring from the bacterium to the electrode, thereby helping us gain a better understanding for the overpotential losses in MFCs. In doing so, we obtain images that show G. sulfurreducens can directly transfer electrons to an electrode surface without the use of pili, and that overpotential losses are likely due to cell death and poor distribution or performance of the bacteria's haem groups. This unique combination of CPEs with C-AFM can also be used for other studies where electron transfer loss mechanisms need to be understood on the nanoscale, allowing for direct visualization of potential issues in these systems.

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Identifiers

DOI

10.1021/acsami.0c10795

Journal

ACS Applied Materials & Interfaces

Year

2020