Printed Organic Transistor-Based Enzyme Sensor for Continuous Glucose Monitoring in Wearable Healthcare Applications

A printed extended-gate-type organic transistor-based enzyme sensor for the continuous monitoring of D-glucose has been developed through a simple modification of the electrical circuit. The sensor is composed of a glucose oxidase (GOx)/ Prussian blue (PB)-modified extended-gate electrode and an Ag/AgCI reference electrode, which are connected to the gate and source electrodes of an organic transistor, respectively. The GOx/PB-modified extended-gate electrode and Ag/AgCl reference electrode were short-circuited by an external resistor to spontaneously induce redox cycling of PB. Continuous monitoring of the source-drain current of the organic transistor for various concentrations of D-glucose was successfully demonstrated in this system. This is the first report of the transistor -based enzyme sensor exhibiting reversible response to the analytes in physiologically buffered solution without the addition of any chemical reagents. This new type of printed organic transistor-based enzyme sensor will greatly contribute to the development of wearable biosensors for non-invasive monitoring of biomarkers in externally secreted bodily fluids such as tears, saliva, and sweat.