Performance assessment of polymer based electrodes for in vitro electrophysiological sensing: the role of the electrode impedance

Medeiros, Maria C. R.; Mestre, Ana L. G.; INÁCIO, PEDRO; Santos, João M. L.; Araújo, Inês; Bragança, José; Biscarini, Fabio; Gomes, Henrique L.

http://hdl.handle.net/10400.1/9670

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Authors

Medeiros, Maria C. R.

Abstract(s)

Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are used to record extracellular signals from autonomous cardiac contractile cells and glioma cell cultures. The performance of these conducting polymer electrodes is compared with Au electrodes. A small-signal impedance analysis shows that in the presence of an electrolyte, both Au and polymer electrodes establish high capacitive double-layers. However, the polymer/electrolyte interfacial resistance is 3 orders of magnitude lower than the resistance of the metal/electrolyte interface. The polymer low interfacial resistance minimizes the intrinsic thermal noise and increases the system sensitivity. However, when measurements are carried out in current mode a low interfacial resistance partially acts as a short circuit of the interfacial capacitance, this affects the signal shape.