Organic electrochemical transistors for signal amplification in fast scan cyclic voltammetry

Fast scan cyclic voltammetry (FSCV) is an electrochemical method commonly used in neuroscience for spatiotemporal measurement of the concentration of dopamine and other electroactive species. Since FSCV involves wide bandwidth measurements of low currents, the technique is normally very sensitive to electrical noise and is typically performed inside a Faraday cage. In order to reduce the electrical noise and to enable measurements in an unshielded environment, we take use of an organic electrochemical transistor (OECT) to amplify the FSCV signals. OECTs based on the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were microfabricated and characterized. A patterned 10 μm gold microelectrode was used as the sensing electrode and the FSCV signal was amplified by the OECT. With this approach, successful measurements of dopamine concentrations in the 10 μM range were performed in a completely unshielded measurement setup. Our results demonstrate how OECTs can successfully be used in an on-site amplification application to characterize biochemical signals, thus open up new trails for flexible multifunctional organic bioelectronics systems.