In vitro electrochemical characterization of polydopamine melanin as a tissue stimulating electrode material
The properties of redox active polydopamine melanin (PDM) films as a coating material for tissue stimulation electrodes were evaluated. PDM films with nanometer-scale thicknesses exhibit dc bias dependent charge injection capacities (CIC) with maximum values of 110 ± 23 μC cm−2 at 0.2 V (vs. Ag/AgCl) and reduce the interfacial impedance compared to inorganic conducting films. PDM films exhibit an asymmetric impedance response to positive and negative dc biases with minimum interfacial impedance at 0.2 V (vs. Ag/AgCl). An explanation for the observed bias-dependent electrochemical behavior is presented.