Development of trypsin biosensor based on ion sensitive field-effect transistors for proteins determination

This new biosensor for protein determination is based on a possibility of translation of either a proton or hydroxyl ion arising during protein hydrolysis in the presence of trypsin by means of ion selective field effect transistor (ISFET). The conditions of trypsin immobilization and main biosensor characteristics were optimized using hydrolysis reaction of nalpha-benzoyl-L-arginine ethyl ester hydrochloride (BAEE). The trypsin was immobilized on the ISFET surface using a co-reticulation process between the enzyme and BSA (4% trypsin. 6% BSA) in saturated glutaraldehyde vapour. The limit of detection of BAEE with this biosensor is 0.5 mM with a linear dynamics range from 0.5 to 5 mM, and sensitivity is about 6 mV/mM. The time of biosensor response was 5-7 min. The possibility of the application of developed biosensor for detection of small penta-peptide, which is used in some cosmetic products, has been demonstrated.