Cyclic Voltammetry and Electrochemical Impedance Spectroscopy of Partially Reduced Graphene Oxide - PEDOT:PSS Transducer for Biochemical Sensing

Electron-transfer kinetics and impedance at the electrode-solution interface affect biosensor performance. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are used to understand the reversibility of electron transfer and impedance at the electrode-solution interface, respectively. Effective surface areas calculated based on the Randles-Sevcik equation for a bare screen-printed carbon electrode (SPCE), a graphene oxide (GO)-poly (3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS)-modified electrode (GO-PEDOT:PSS/SPCE), a partially reduced graphene oxide-PEDOT:PSS-modified electrode (prGO-PEDOT:PSS/SPCE), and glucose oxidase (GOx) crosslinked with glutaraldehyde on partially reduced graphene oxide-PEDOT:PSS-modified electrodes (GOx/prGO-PEDOT:PSS/SPCE) are 0.0717 mm
²
, 0.0794 mm
²
, 0.219 mm
²
, and 0.160 mm
²
, respectively. Nyquist plots from EIS show charge transfer resistance (R
_ct
) of 430 μΩ, 148.2 Ω, 200.7 Ω, and 209.6 Ω, respectively, for the same electrodes. The high effective surface area and the Rct of prGO-PEDOT:PSS/SPCE indicate that the prGO-PEDOT:PSS composite is suitable as a transducer layer for glucose biosensing.