Influence of poly(styrene sodium sulfonate) grafted silicone breast implant’s surface on the biological response and its mechanical properties

Abstract

Prior to its commercialization, a biomaterial must fulfill the regulation in place. The International Organization for Standardization outlines the requirements needed for a material in order to guarantee safety and quality. In previous work, we have successfully grafted a bioactive polymer known as poly(styrene sodium sulfonate) – (polyNaSS) on silicone breast implants’ surfaces using UV irradiation. This paper intends to study the effect of the polyNaSS grafting parameters. It includes the study of (i) the effect of only UV irradiation and (ii) the presence of the polyNaSS grafted silicone on both the mechanical properties of the material and the biological response using the L929 fibroblast cell line for biocompatibility investigations. PolyNaSS aims to overcome the lack of biocompatibility issues, but the grafting process should have a minimal impact on the surface’s properties. The tensile strength and swelling tests showed no apparent modification before and after grafting in crosslinking densities and elasticity moduli. That confirms the impactless aspect of the grafting protocol on the material’s mechanical properties. Surface roughness was investigated by atomic force microscopy to understand cell behavior on surfaces upon various treatments. Biocompatibility tests showed that the grafting of polyNaSS significantly enhanced cell adhesion and viability compared to a non grafted silicone. Overall, polyNaSS confers a highly suitable surface for fibroblasts, demonstrating their active forms (spindle-shaped). This was assessed by optical microscopy, scanning electron microscopy, and atomic force microscopy.