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/AgCl 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. Don′t shed a tear: A printed extended‐gate type organic transistor‐based enzyme sensor for the continuous monitoring of D‐glucose is developed through a simple modification of the electrical circuit. This new type of sensor will contribute to the development of wearable biosensors for non‐invasive monitoring of biomarkers in externally secreted bodily fluids.