Dynamic modelling and simulation of reactive transport phenomena in an amperometric blood glucose biosensor

The treatment of diabetes as well as several other diseases which affect millions of patients worldwide strongly depend on deploying affordable technologies for frequent and accurate monitoring of blood glucose concentrations. Both theoretical and experimental investigations of novel blood glucose biosensor concepts pave the way for fast efficiency analysis of candidate biosensor designs. Recent studies have addressed the operation of amperometric biosensors, within which a combination of an enzymatic reaction and an enzyme deposited on an electrode allows for conclusive blood glucose detection. This paper models a single droplet on blood on an amperometric glucose biosensor to investigate the sensitivity of sensor performance to varying transport phenomena parameter values. The work presents a comprehensive sensitivity analysis, based on a new two-dimensional spatiotemporal model (constructed in MATLAB) which studies the combined reactive transport phenomena within a blood droplet deposited on an enzyme-coated surface. The sensitivity analysis explores the variation of electrode response (current density) and concentration profiles throughout the droplet and the enzyme layer subject to varying initial conditions and component diffusivities. Results clearly indicate a strong dependence of output profiles on the said sensitivity parameters: ensuring high current density (especially for small droplet volumes) is a prerequisite for developing reliable glucose biosensors of high accuracy and precision.