ENFETs and Conductometric Biosensors with Additional Membranes: Reduction of Influence of Buffer Capacity on the Sensor Response and Extension of its Dynamic Range

This chapter presents a study analyzing ENFETs and conductometric biosensors with additional membranes. In the study, glucose-, urea- and penicillin-sensitive enzyme sensors (ENFETs and conductometric biosensors) were prepared by cross-linking corresponding enzyme with bovine serum albumin in saturated glutaraldehyde vapor on the sensitive area of transducers. Different additional membranes (bovine serum albumin, polyvinilbutyrol, NAFION and so on) were deposited on the top of the enzyme layers by a spin-coating procedure. Additional membranes resulted in a substantial reduction of the buffer concentration influence on the sensor response and in an extension of its dynamic range. The obtained results demonstrate the possibility to improve and to adjust the characteristics of the biosensors using different additional membranes with controlled thickness and morphology. Comparison of properties of the biosensors developed, demonstrates a better performance of the sensors with the additional membrane. The obtained results are interpreted in terms of perm-selective properties of the additional membrane formed.