Bioelectrical signal detection using conducting polymer electrodes and the displacement current method

Conducting polymer electrodes based on poly(3,4- ethylenedioxythiophene):polystyrene sulfonate were used to record electrophysiological signals from autonomous cardiac contractile cells present in embryoid bodies. Signal detection was carried-out by measuring the displacement current across the polymer/electrolyte double-layer capacitance, and compared with voltage detection. While for relatively low capacitance electrodes the voltage amplification provides higher signal quality, for high capacitive electrodes the displacement current method exhibits a higher signal-to-noise ratio. It is proposed that the displacement current method combined with high capacitive polymer-based electrodes is adequate to measure clusters of cells and whole organs. Our approach has a great potential in fundamental studies of drug discovery and safety pharmacology.