Application of voltammetry in biomedicine - Recent achievements in enzymatic voltammetry

Protein-film voltammetry (PFV) is considered the simplest methodology to study the electrochemistry of lipophilic redox enzymes in an aqueous environment. By anchoring particular redox enzymes on the working electrode surface, it is possible to get an insight into the mechanism of enzyme action. The PFV methodology enables access to the relevant thermodynamic and kinetic parameters of the enzyme-electrode reaction and enzyme-substrate interactions, which is important to better understand many metabolic pathways in living systems and to delineate the physiological role of enzymes. PFV additionally provides important information which is useful for designing specific biosensors, simple medical devices and bio-fuel cells. In the current review, we focus on some recent achievements of PFV, while presenting some novel protocols that contribute to a better communication between redox enzymes and the working electrode. Insights to several new theoretical models that provide a simple strategy for studying electrode reactions of immobilized enzymes and that enable both kinetic and thermodynamic characterization of enzyme-substrate interactions are also provided. In addition, we give a short overview to several novel voltammetric techniques, derived from the perspective of square-wave voltammetry, which seem to be promising tools for application in PFV.