Surface processes in artificial organs. An overview

The area of contact between an artificial organ and the biological environment results from the inner and outer surface of the organ. The lifetime of the organ determines the properties of the material's surfaces in use. Reactions occur in both directions--from the surface to the body and vice versa, from the body to the surface. Centers of nucleation and points for destruction propagation due to attacks of body fluids are irregularities of the surface structure and gradients in the chemical composition of both material and fluid. Some of the mechanisms that occur are initiated or at least promoted by mechanical factors. Some of the body-surface interactions that take place are: adsorption, degradation, corrosion, calcification, fatigue, embrittlement, and wear; these limit the lifetime of artificial organs. The strength of the interaction depends on the substituted function, the design, and the locus of implantation.