Modeling the Cyclic Dynamics of a Tyrosinase-Based Catechol Sensor

Abstract

A cyclic redox reaction, mediated by L-ascorbic acid and involving catechol and 1,2-benzoquinone, forms the basis of the mathematical model developed for a tyrosinase-based amperometric biosensor. The system is governed by a ping-pong bi-bi mechanism and modeled using nonlinear reaction-diffusion equations under steady-state conditions. The Homotopy Perturbation Method (HPM) is applied to derive approximate analytical solutions, which show excellent agreement with numerical results. The effects of key dimensionless parameters, particularly the Thiele modulus, are analysed to assess sensor performance. Results highlight the critical balance between reaction kinetics and diffusion in determining sensitivity and current response. The proposed model provides a valuable analytical tool for optimising biosensor design in both clinical and environmental applications.