Impact of Protein Fouling on the Charge Injection Capacity, Impedance, and Effective Electrode Area of Platinum Electrodes for Bionic Devices

The impact of protein fouling on platinum electrodes was assessed by electrochemical methods. Protein fouling affected the electrode potential and charge transfer through the electrode-solution interface. Adsorbed proteins partially blocked the electrode, with no charge passing through blocked regions. The electrochemical theory and methodology for investigating partially blocked electrodes is fully presented, applied to protein adsorption, and the implications for bionics applications are discussed. The partially blocked electrode had a reduced admittance, and increased impedance and polarization resistance consistent with a smaller effective electrode area. The charge storage capacity and charge injection capacity decreased after protein adsorption. The effective electrode area was assessed by impedance and cyclic voltammetry. The diffusion profile towards the partially blocked electrode was mixed between linear and radial diffusion.