Biocompatibility considerations at stimulating electrode interfaces

The choice of biocompatible stimulating electrodes for various biomedical applications varies with the type of electrode-tissue interface, biomolecules present, electrolyte background, preparation of electrode, interfacial potential, current density, electrode material, porosity, geometry, and inflammatory response. Illustrative examples are given to demonstrate the importance of these parameters. Topics discussed are: A) DC electrodes applied to partially keratinized epithelial membranes; B) Variation of the electrical impedance and biocompatibility of stimulating electrodes with electrode potential and surrounding pH; C) Influence of electrode geometry, porosity and pore size on biocompatibility; D) Body defense mechanisms at the sites of implantable stimulating electrodes; E) Thrombus formation at stimulating electrode interfaces and F) Sterilization of electrodes to ensure biocompatibility.