Modification of silicone elastomers with Bioglass 45S5® increases in ovo tissue biointegration

Silicone is an important material family used for various medical implants. It is biocompatible, but its bioinertness prevents cell attachment, and thus tissue biointegration of silicone implants. This often results in constrictive fibrosis and implant failure. Bioglass 45S5® (BG) could be a suitable material to alter the properties of silicone, render it bioactive and improve tissue integration. Therefore, BG micro- or nanoparticles were blended into medical-grade silicone and 2D as well as 3D structures of the resulting composites were analyzed in ovo by a chick chorioallantoic membrane (CAM) assay. The biomechanical properties of the composites were measured and the bioactivity of the composites was verified in simulated body fluid. The bioactivity of BG-containing composites was confirmed visually by the formation of hydroxyapatite through scanning electron microscopy as well as by infrared spectroscopy. BG stiffens as prepared non-porous composites by 13% and 36% for micro- and nanocomposites respectively. In particular, after implantation for 7 days, the Young's modulus had increased significantly from 1.20 ± 0.01 to 1.57 ± 0.03 MPa for microcomposites and 1.44 ± 0.03 to 1.69 ± 0.29 MPa to for nanocpmosites. Still, the materials remain highly elastic and are comparably soft. The incorporation of BG into silicone overcame the bioinertness of the pure polymer. Although the overall tissue integration was weak, it was significantly improved for BG-containing porous silicones (+72% for microcomposites) and even further enhanced for composites containing nanoparticles (+94%). These findings make BG a suitable material to improve silicone implant properties. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1180-1188, 2019.