Biocompatibility of electrodes for stimulation are difficult to maintain
homeostasis. Noble metal stimulating electrodes which are normally
biocompatible on keratinized tissue become very non-biocompatible when they
are interfaced with nonkeratinized tissue in an area such as the oral cavity.
Composite electrodes have been made biocompatible in the oral cavity even at
current densities larger than 1 μA/mm2. Electrodes used in potential readings
require that the anodic and cathodic polarization remain minimal. Silver-silver
chloride electrodes are minimal. Silver-silver chloride electrodes are not always
reversible. The range of pH, voltages and current densities when silver-silver
chloride are not reversible are presented. Recently at Drexel University reliable
silver coatings inside and outside of medical catheters have been fabricated to act
as antimicrobial to a variety of bacteria. Noble and nonnoble metals have been
combined in coatings with silver to enhance the antimicrobial action.