Spider Silk Coatings as a Bioshield to Reduce Periprosthetic Fibrous Capsule Formation

Abstract

Medical grade silicones have been employed for decades in medical applications. The associated long‐term complications, such as capsule formation and contraction have, however, not been fully addressed yet. The aim of this study is to elucidate if capsule formation and/or contraction can be mitigated by veiling the surface of the silicone during the critical phase after implantation. Medical grade silicone implants are homogeneously coated with a micrometer thin layer of recombinant spider silk proteins. Biocompatibility analysis in vitro and in vivo focuses on specific physiological reactions. Applying quantitative methods for the determination of marker‐specific gene expression and protein concentration, it is detected that the silk coating inhibits fibroblast proliferation, collagen I synthesis, and differentiation of monocytes into CD68‐positive histiocytes. It significantly reduces capsule thickness, post‐operative inflammation, synthesis and re‐modeling of extracellular matrix, and expression of contracture‐mediating factors. Therefore, coatings made of recombinant spider silk proteins considerably reduce major post‐operative complications associated with implantation of silicone‐based alloprosthetics, such as capsular fibrosis and contraction, rendering spider silk coatings a bioshield for such implants.