Covalent vectored binding of functional proteins by bifunctional crosslinking at silicone interfaces

In the daily clinical routine, numerous synthetic medical devices are implanted in the human body, either temporarily or permanently. The synthetic material most often implanted is polydimethylsiloxane (silicone). Numerous studies have demonstrated that silicone is encompassed in a connective tissue capsule by the body, preventing integration into the surrounding tissue. This can result in complications. The aim of our study was to develop a simple procedure to functionalize the silicone surface, thereby positively affecting the material's biocompatibility. By combining a silanization with the use of ester activation, a reactive amino group is generated, which can bind any free carboxyl group. Directional crosslinking of a near-infrared-conjugated fluorophore antibody to the activated silicone surface could be demonstrated on a dose-dependent basis. The redox reaction at a silicone surface coated with an HRP-conjugated antibody caused by the addition of NBT/BCIP could be shown. Covering the silicone discs with an anti-FAS-antibody coating followed by a coincubation with FAS-sensitive T-cells allowed highly significant detection of caspase-3. In summary, our crosslinking procedure enables the stable binding of proteins without the loss of biological function. Through this process, silicones could be endowed with new functions which could improve their biocompatibility.