Structural characterization and in vitro bioactivity assessment of SiO2–CaO–P2O5–K2O–Al2O3 glass as bioactive ceramic material

The potassium based bioactive glasses have shown a better biocompatibility than soda containing bioactive glasses. Therefore, we have prepared a bioactive glass system containing potassium oxide and substituted with Al2O3 for further enhancement of bioactivity, physico-chemical properties, mechanical strength as well as its behavior to human osteosarcoma cells. The prepared bioactive glasses have a general formula, 42SiO2–34CaO-6 P2O5–(18−x) K2O, where x=0, 0.5, 1, 1.5 and 2.5 mol% of Al2O3. The in-vitro bioactivity of these samples was assessed by immersion in SBF solution for different time periods under physiological conditions. The formation of hydroxy carbonate apatite (HCA) layer on the surface of the glass samples after SBF treatment was confirmed by FTIR, XRD and SEM. The partial substitution of Al2O3 for K2O in glass demonstrated a significant increase in mechanical properties such as compressive strength and elastic modulus, respectively. The cytotoxicity, cell viability, proliferation, apoptosis and cell attachment were assessed using human osteosarcoma U2-OS cell lines. The cell culture studies demonstrated that the samples containing high concentration of Al2O3 showed a cytotoxic nature against cell lines. But the blood compatibility showed that all the samples were tolerant. Finally, this study clearly concludes that the optimization of Al2O3 in present potash based bioactive glasses would be potential biomaterials for biomedical applications.