Comparison of carbon and ITO membrane performance as TiO2 substrate material and applied to Uric Acid biosensor using Differential amperometric readout circuit

In this paper, screen-printed carbon electrode and glass indium tin oxide electrode were used, and the membrane for the use of our research was prepared by the sol-gel method with each sensitivity under the linear measuring range was 53 mV/pH and 48 mV/pH. Nevertheless, by using the principle of EGFET we build up the enzyme sensitive field effect transistor (ENFET) which the biomedical uricase membrane was fixed onto the TiO₂ film by using physical immobilization - gel entrapment, and the enzyme membrane can only redox to certain substances which will be scanned and analyzed by cyclic voltammetry. Uric acid amperometric signal will be measured by using differential input, which combines pH sensor and the uric acid sensor in order to reduce the affection from background environment. The detection of this research on uric acid, Enzyme/TiO₂/carbon and Enzyme/TiO₂/ITO adopted differential amperometric measuring system for voltage fixed at 0 V shows a fine linearity and the sensitivity of -1376(mu Acm^-2) (4-mg/dl)^-1, -0.848 (mu Acm^-2) (4mg/dl)^{- 1}.