[Biomaterials].

Biomaterials--materials used for the elaboration of systems designed for human implantation or organ substitutes--can be classified as metals and alloys, ceramics and polymers. Their uses are largely diversified, for soft and hard tissues replacement. Interactions rise between biological environment and implants, the mechanisms of them not always known: inflammatory response, corrosion and degradation of materials leading to leaching of some constituents possibly toxic and alteration of their mechanical properties. Blood interfacing materials introduce some particular problems of hemocompatibility. The matching of implant to biological medium, in other words, its biocompatibility has to be a priori evaluated, but until now no in vitro or in vivo evaluation method is fully reliable.