Application of charged polymeric materials as additional permselective membranes for modulation of the working characteristics of penicillin sensitive ENFETs

A penicillin-sensitive biosensor based on pH-sensitive field effect transistors was prepared by cross-linking penicillinase with bovine serum albumin in a saturated glutaraldehyde vapour on the sensor chips. Additional Nafion or PVP (poly(4-vinylpyridine-co-styrene)) membranes were deposited on the top of the enzymatic and reference membranes of penicillin biosensors by a spin-coating process. Working characteristics of penicillin sensitive ENFETs without and with additional membranes were tested. It was shown that the presence of such permselective additional layers on the top of the enzymatic membranes modulates but does not improve the main working characteristics of the ENFET, such as the detection limit, dynamic range, dependence of the sensor response on buffer capacity and ionic strength of the analysed sample.