Functionalization of silicone rubber surfaces towards biomedical applications

The surface of a biomaterial has been found to be of prime importance in determining the in vivo performance and host acceptance of the material. The biocompatibility of implantable devices remains a critical issue in limiting device longevity and functionality. Growing efforts have and are being made to further understand the interactions between biomaterials surface physicochemical and cell mediated processes, with the ultimate role of defining the major rules regulating the biomaterial biocompatibility. This review focuses on polydimethylsiloxane polymers, specifically silicone rubber, a well-known biomaterial for the production of prostheses that holds various attractive properties. Despite its widespread use, the extensive hydrophobicity of silicone rubber is disadvantageous and often demands further (surface) modification to improve its performance in vivo. Hydrophobic surfaces tend to adsorb proteins from the surrounding biological environment, subsequently triggering microbial adhesion and biofilm formation. Numerous strategies have been investigated to overcome foreign body reactions induced by the implanted devices. These strategies, their advantages and limitations, as well as state of the art concerning the multidisciplinary field of biomaterial surface modification are discussed.