USE OF SUBSTRATE COATED ELECTRODES AND AC-IMPEDANCE SPECTROSCOPY FOR THE DETECTION OF ENZYME-ACTIVITY

A biosensor for collagenase detection was developed which detected the change in impedance caused by proteolytic digestion of gelatin coated interdigitated gold electrodes. The concentration of gelatin in the l ayer did not greatly affect the impedance measurements. Enzyme degrada tion of the layer produced a rapid rise in impedance when a critical t hickness was reached. The change in impedance with protease digestion was correlated with solubilisation of the gelatin layer as measured by weight loss of the gelatin layer from the sensor surface. The respons e time of the device was greatly reduced by stirring the fluid around the biosensor. The ability to detect the gelatin coating on the sensor was severely impaired by the presence of electrolyte. The implication s of these findings for further biosensor development are discussed. ( C) 1998 Elsevier Science S.A. All rights reserved.