Study the characteristics of uricase biosensor based on the extended gate field effect transistor

Abstract

An enzyme field effect transistor (EnFET) device for a uric acid biosensor is described. First, we use a separative structure of the extended gate field effect transistor (EGFET) to detect a standard pH buffer solution. Specific membranes can detect the H/sup +/ and OH/sup -/ in solutions, so sensors that are deposited thin films of TiO/sub 2/ or other materials are pH array sensors. In the experiment, we use gel entrapment to immobilize the enzyme. The stability of the device is very significant in measurement. The paper describes and compares some novel readout circuits applied to the extended gate field effect transistor. In addition, we can obtain a high pH sensitivity and a linear response of about 55.11 mV/pH. The response time of the sensor to different concentrations of uric acid is 40 sec, the maximum voltage variation is 88 mV in a 5M phosphate buffer at pH 6.5 and the linear range of the calibration curve is 0.05 to 0. 15 mg/dL.