The influence of the diffusion space geometry on behavior of some processes in biochemistry and electrochemistry

Modelling of the amperometric biosensors based on carbon paste electrodes encrusted with a single inhomogeneous microreactor is analyzed. The mathematical model of the biosensor operation is based on nonstationary diffusion-reaction equations containing a non-linear term given by Michaelis-Menten function. Modelling of a simple redox-electrode reaction, involving two soluble species, is also considered. The model of the electrode behaviour, taking into account the resist layer of the partially blocked electrodes, was expressed as a system of differential equations of the diffusion type with initial and boundary conditions. The mathematical model generalizing both processes: biochemical and electrochemical is presented in this paper. The generalized problem was solved numerically. The finite-difference technique was used for discretization of the model. Using the numerical solution of the generalized problem, the influence of the size, shape and position of a microreactor as well as the thickness of the resist layer on the current dynamics was investigated. The dependence of the maximal current on the geometry of the diffusion space was also investigated