Computational Modelling of Membrane Biosensors Acting in Stirred and Non-stirred Solutions

This paper presents mathematical models of potentiometric as well as amperometric biosensors, based on an electrode covered with an enzyme membrane. The models involve three regions: the enzyme layer where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region, where the analyte concentration is maintained constant. Using computer simulation the influence of the thickness of both the enzyme and the diffusion layers on the biosensor response was investigated. The effect of the diffusion layer on the biosensor response was evaluated for different conditions of the enzymatic reaction and types of mixers. This paper deals also with the conditions when the mass transport in the exterior diffusion region may be neglected to simulate the biosensor response assuming the buffer solution is well-stirred and in powerful motion. The digital simulation was carried out using the finite difference technique.