Electrochemistry of redox enzymes: from functional enzyme immobilization to enzymatic bio-electrochemical devices (tutorial)

Electrochemistry of redox enzymes is a multidisciplinary field, and students who join labs specialized in bio-electrochemistry have various backgrounds: chemistry, biology, biotechnologies, nanotechnologies, physics, etc., so that their level in the involved disciplines is often heterogeneous, and they sometimes lack the basic knowledge about either of the fields concerned by their project (physical chemistry, electrochemistry, enzymology, etc.). Projects that gather experienced researchers from these different areas also sometimes suffer from a lack of understanding between the partners. This tutorial, which follows a lecture given at the first winter school of the French group of bio-electrochemistry (GFB), aims at guiding newcomers in the field and provides advice for more in-depth and specialized literature. It seeks to provide a solid theoretical and experimental foundation. Redox enzymes and the basic methods of immobilization at the electrode are introduced. The mechanisms of direct and mediated electron transfers are explained. An important electrochemical method, cyclic voltammetry, is explained, and the article describes how to extract information about enzyme/electrode and catalytic reactions. Finally, the tutorial presents two enzymatic bio-electrochemical devices, enzymatic fuel cells and enzymatic biosensors, and provides a guide for their electrochemical characterization.