In vitro degradability and bioactivity of mesoporous CaO-MgO-P₂O₅-SiO₂ glasses synthesized by sol–gel method

Two glasses of the CaO-MgO-P₂O₅-SiO₂ system with different MgO contents (0 and 10 mol%, respectively) have been synthesized by sol–gel method. The degradation of glass samples was evaluated through the weight loss in the tris-(hydroxymethyl)-aminomethane and hydrochloric acid (Tris–HCl) buffer solution, and the in vitro bioactivity was assessed by determining the changes in surface morphology and composition after soaking in a simulated body fluid. Formation of the apatite-like layer on glasses surface was studied by means of X-ray diffraction, Fourier-transform infrared, scanning electron microscopy. Results indicate that, with the partial substitution of MgO for CaO in glass composition, the glass degradation decrease and the formation of apatite-like layer is delayed. Furthermore, it is observed that the glass bioactivity is relative to its dissolution, and the effects of MgO on glass degradability and bioactivity may be attributed to the influence of ionic field strength and distinct bonding configuration of glass.