Structural behavior and in vitro bioactivity evaluation of hydroxyapatite-like bioactive glass based on the SiO2-CaO-P2O5 system

Abstract Silicate bioglass is of great importance in bone engineering because of its excellent bioactivity and osteogenic effects. In this study, hydroxyapatite-like bioactive glass based on the xSiO2-CaO-P2O5 (x = 30, 45, 60 and 90 mol.%, Ca/P = 1.67) system was synthesized by the sol-gel method, and the corresponding structural evolution, apatite-forming ability and cytotoxicity were systematically investigated. The results suggest that both a higher heat treatment temperature and a lower SiO2 content increase the crystallinity tendency of the bioglass, and the samples become obviously compact as the SiO2 amount increases from 30 to 90 mol.%. Compared with the samples with higher SiO2 content, the 30Si sample shows more remarkable internal connected mesoporous structures, with a higher specific surface area up to 129.12 m2/g, exhibiting excellent hydroxyapatite formation in simulated body fluid. Moreover, no obvious inhibitory effect was presented on human periodontal ligament cells (hPDLCs) for any of the silicate glass samples.