FABRICATION AND CHARACTERIZATION OF ENFET DEVICES FOR BIOMEDICAL APPLICATIONS AND ENVIRONMENTAL MONITORING

We have realized an enzyme-modified FET device (ENFET) in which the enzyme has been chemically linked to the FET surface by means of a layer of polymerized [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEAPS). The enzyme has been bound to the amino functional groups of the polysiloxane surface together with bovine serum albumin by using cross-linking agents, such as glutaraldehyde, and the obtained enzymatic membrane has been characterized by FT-IR directly onto the gate surface. The polysiloxane layer has proved to be a good interface between the enzyme and the device surface allowing a biosensor with the characteristics of good stability and reproducibility to be obtained. In this paper two examples of the fabrication and the performances of this kind of biosensor for urea determination in biomedical applications and pesticide detection in environmental control are shown, employing immobilized urease or acetylcholinesterase ENFET devices, respectively.