Biofunctionalization of silicone rubber with microgroove-patterned surface and carbon-ion implantation to enhance biocompatibility and reduce capsule formation

PURPOSE Silicone rubber implants have been widely used to repair soft tissue defects and deformities. However, poor biocompatibility can elicit capsule formation, usually resulting in prosthesis contracture and displacement in long-term usage. To overcome this problem, this study investigated the properties of silicone rubber materials with or without a microgroove-patterned surface and with or without carbon (C)-ion implantation. MATERIALS AND METHODS Atomic force microscopy, X-ray photoelectron spectroscopy, and a water contact angle test were used to characterize surface morphology and physicochemical properties. Cytocompatibility was investigated by a cell adhesion experiment, immunofluorescence staining, a Cell Counting Kit-8 assay, and scanning electron microscopy in vitro. Histocompatibility was evaluated by studying the inflammatory response and fiber capsule formation that developed after subcutaneous implantation in rats for 7 days, 15 days, and 30 days in vivo. RESULTS Parallel microgrooves were found on the surfaces of patterned silicone rubber (P-SR) and patterned C-ion-implanted silicone rubber (PC-SR). Irregular larger peaks and deeper valleys were present on the surface of silicone rubber implanted with C ions (C-SR). The silicone rubber surfaces with microgroove patterns had stable physical and chemical properties and exhibited moderate hydrophobicity. PC-SR exhibited moderately increased dermal fibroblast cell adhesion and growth, and its surface microstructure promoted orderly cell growth. Histocompatibility experiments on animals showed that both the anti-inflammatory and antifibrosis properties of PC-SR were slightly better than those of the other materials, and there was also a lower capsular contracture rate and less collagen deposition around implants made from PC-SR. CONCLUSION Although the surface chemical properties, dermal fibroblast cell growth, and cell adhesion were not changed by microgroove pattern modification, a more orderly cell arrangement was obtained, leading to enhanced biocompatibility and reduced capsule formation. Thus, this approach to the modification of silicone rubber, in combination with C-ion implantation, should be considered for further investigation and application.