Printable Biosensors based on Organic Electrochemical Transistors with a Platinized Gate Electrode

Abstract: There is a great demand for low-cost disposable sensors in a variety of markets, such as the food chainand health care. No assay is performed more than that of glucose and approximately 85 % of the entirebiosensor market accounts for glucose biosensors. Each year, 6 billion glucose assays are performed andthe majority of them are based on electrochemical detection. Organic electrochemical transistors(OECTs) have favorable properties in terms of low operating voltages and have previously been used asbase for electrochemical detection of glucose. A low-cost disposable biosensor can be achieved by theuse of high throughput printing techniques. Up until now, no printable biosensors based on organic electrochemicaltransistors have been developed. In this thesis a printable miniaturized prototype for a glucose biosensor based on an OECT with a platinizedgate electrode has been designed, developed and evaluated. The biosensor has been functionalizedwith the enzyme glucose oxidase. Different platinum deposition techniques have been used to depositplatinum onto the printed carbon gate electrode: electrodeposition, platinum nanoparticle solutiondeposited either by inkjet printing or pipetting and thermal evaporation. The gate electrodes were characterized with cyclic voltammetry in hydrogen peroxide, ferricyanide andglucose. The characterizations revealed no significant differences between the different deposition techniques.However, with gate electrodes produced by printed carbon followed by electrodeposition ofplatinum it was possible to sense glucose in a concentration in the range of the values for diabetic persons.Thus, the electrodes are a promising option as gate electrodes in a glucose biosensor based on anOECT. The characteristics of the OECT revealed that the responses resembled a transistor.