MODELING MASS-TRANSFER WITH ENZYMATIC-REACTION IN ELECTROCHEMICAL MULTILAYER MICROREACTORS

Electrochemical biosensors were used to develop a numerical model of t ransient mass transfer coupled with enzymatic reactions in thin multil ayer microstructures. A finite volume method integrates the partial de rivative mass-balance equations making the model very versatile. With a multilayer physical description, general nonlinear enzymatic kinetic s and efficient space discretization, the model could be applied to va rious devices under a broad range of physicochemical conditions. Theor etical results were validated according to experimental data obtained with three different biosensors involving homogeneous or heterogeneous enzymatic catalyses. Model predictions are further discussed for a bi enzymatic immobilized enzyme system. The biosensor transient behavior depended strongly on the location of the enzymes in the device and on the mass-transport features. A transient maximum on the current-time c urves was predicted accurately by the model. This could be used to imp rove the biosensor performance. The model can also be a useful framewo rk for designing new electrochemical microreactors.