Biocompatibility issues of implanted polymeric materials

Polymers remain the most versatile class of biomaterials, being extensively applied in medicine and biotechnology, as well as in the food and cosmetics industries. Applications include surgical devices, implants and supporting materials. The biocompatibility and immunocompatibility of polymeric materials is of fundamental importance for their possible therapeutic uses. Implanted systems are in direct and sustained contact with the tissues, and some of them degrade in situ. Thus, both the material itself and its degradation products must be devoid of toxicity. The knowledge and understanding of the criteria and mechanisms determining the biocompatibility of biomaterials are therefore of great importance. The biocompatibility of a polymer depends on the specific adsorption of proteins to the polymer surface and the subsequent cellular interactions. The first contact is between the surface of the polymer and the organism (blood and other tissues) and results in a 'foreign-body' reaction. Owing to the nature of these interactions, surface modification strategies have been used to optimize specific surface properties (e.g. charge, adhesion, hydrophilicity) of the implanted polymeric materials.