Coating evolution with an implantable biological battery.

A cathode of smooth platinum in a right endoatrial position and an anode of Domal magnesium were used to construct a hybrid bioelectric battery designed to power a pacemaker. In use the cathode is gradually covered by a coating consisting of a crystalline layer and a layer of connective tissue. This coating is responsible for the system change in the reduction process at the cathode level: the transfer from an oxygen to a hydrogen system. This system change causes a voltage drop in the bioelectric battery. This paper deals with oxygen diffusion across the tissue layer, as well as with various spectral and chemical analyses. A high level of calcium and phosphorus in the different analyses carried out seems to show that the presence of these elements is related to the coating of the cathode. The effect on the formation of the coating of the position of the cathode is also discussed.