Glucose sensor based on organic thin film transistor using glucose oxidase and conducting polymer

Abstract

An organic thin film transistor (OTFT)-based glucose sensor, with a channel consisting of glucose oxidase enzyme (GOx) immobilized with poly(3,4-ethylenedioxythiophene–poly(styrene-sulfonate) (PEDOT–PSS) conducting polymer film, has been investigated. GOx was immobilized on PEDOT–PSS conducting polymer film using a simple cost effective spin-coating technique, and was entrapped in the polymer matrix during electrochemical polymerization. Subsequently, the sensor was encapsulated within a cellulose acetate membrane to prevent dissolution of GOx and PEDOT–PSS matrix in glucose solution (glucose in DI water). The resulting device characteristics were determined using a Keithley electrical measurement system. A linear increase in the OTFT drain current was observed resulting from the increase in glucose concentration. The sensitivity of the developed glucose sensor was determined to be 1.65 μA per 1 mM of glucose concentration. A linear range of response was found from 1.1 to 16.5 mM of glucose, with a response time of 10–20 s. The results obtained are indicative that the reported OTFT-based glucose sensor retains the enzyme bioactivity and can be applied as a glucose biosensor.