Rapid synthesis of nano bioactive glass ceramic S53P4 using the special sol-gel method

A bioactive glass–ceramic with the composition 53SiO₂-20CaO-23Na₂O-4P₂O₅ (wt%) (S53P4) was synthesized using a modified sol–gel route. In this process, Ca(NO₃)₂·4 H₂O, NaNO₃, TEOS, and TEP were hydrolyzed in hot water to form a homogeneous sol, which was subsequently transformed into a gel inside a hydrothermal reactor. The wet gel was then dried by freeze-drying to preserve its porous structure and finally calcined at high temperature to obtain the glass–ceramic material. The synthesized product was characterized by XRD, SEM-EDX, TEM, BET, and ICP-OES analyses. Bioactivity was examined by immersing the powder in simulated body fluid (SBF), while biocompatibility was evaluated using L-929 fibroblast cells. The results show that the obtained glass–ceramic exhibits a nanostructure with an average particle size of 22.86 nm, high porosity, large specific surface area (311.51 m²/g), and significant pore volume (0.791 cm³/g). Upon immersion in SBF, a hydroxyapatite layer formed within 3 days, confirming excellent bioactivity. Cytotoxicity tests demonstrated high biocompatibility, with cell viability exceeding 90% at all extract concentrations and reaching up to 134% at a 25% extract level.