Anti-inflammatory properties of triblock siloxane copolymer-blended materials

Implantable biomaterials often trigger a variety of adverse responses. Because polydimethyl siloxane surfaces have good hemo- and bio-compatibility, it is generally believed that surface biocompatibility may be improved by modifying biomaterial surfaces with silicone-like properties. For this, we developed a series of polycaprolactone–polydimethylsiloxane–polycaprolactone (PDMS–PCL) copolymers. By mixing the substrate material—polyvinyl chloride—with low concentrations (1.2 and 2.4%) of the PDMS–PCL copolymer, we generated materials with silicone-like surface properties as reflected by increased surface silicon content and surface contact angles. We assessed the biocompatibility of these surfaces in vitro and found that the addition of PDMS–PCL significantly reduced the percentages of surface-‘denatured’ fibrinogen, a critical element of genesis of many adverse responses to implanted biomaterials. Indeed, using an animal implantation model, we find that PDMS–PCL-blended materials triggered significantly weaker inflammatory responses than did polyvinyl chloride, the substrate control. The results from these experiments suggest that the use of PDMS–PCL additives (2.4%) in polymer blends is a useful means of camouflaging the substrate surface properties and improving the biocompatibility of biomaterials.