Chapter 4
Mathematical Modeling of Enzymatic Sensors
4.1 Introduction
A particular feature of enzymatic biosensors is the dynamic character of the sensor processes. Once the substrate-containing solution comes into contact with the sensor, conversion of substrate under the catalytic action of the enzyme begins and induces concentration gradients. As a result, diffusion of both reactant and product is sustained as long as the substrate is available. Consequently, modeling of enzymatic biosensors is a problem of mass transfer coupled with a chemical reaction that is catalyzed by an immobilized catalyst. From this standpoint, an enzymatic sensor can be viewed as a small enzyme reactor integrated with a transduction device.
The expected output of the modeling approach is the response function that gives the correlation between the sensor response and the substrate concentration in the test solution. Modeling reveals the essential working parameters and is of particular importance for the rational design of the sensor. Also, it allows predicting important features, such as the extent of the linear calibration range, the limit of detection, the response time and possible interferences.
The key assumption in the present approach is that the transduction response is a function of the concentration of a product at the transducer interface. Therefore, the main goal of the mathematical modeling is to find a relationship between the product concentration at the transducer surface and the ...
