Modeling enzymatic and electrochemical cascade reactions at the three-phase interface enzyme electrode

The enzyme electrode based on enzymatic and electrochemical cascade reactions is a golden approach for detecting various biomarkers. How the interfacial architectures of a promising three-phase interface enzyme electrode can influence the cascade reactions and electrode performance, however, remains unclear. In this study, a mathematical model has been developed to describe intraphase and interphase mass transfer, coupled with cascade reactions. The results reveal that the interfacial architectures determine the mass transfer of oxygen (substrate of oxidase) and H2O2 (enzymatic product) in the cascade reactions, hence affecting the electrode current. Generally, thinner pore walls facilitate the mass transfer of oxygen, thereby enhancing the enzymatic kinetics and H2O2 production. Meanwhile, smaller pore sizes shorten the diffusion pathway of H2O2 to the electrode surface, thereby increasing the electrocatalytic reaction rate. This work provides an efficient in silico tool for the design of high-performance three-phase enzyme electrodes.