Formulating Single Phasic Silicorhenanite (α- and β-Na2Ca4(PO4)2SiO4) Bioactive Glass Materials Competing with Commercial Crystalline Hydroxyapatite Bone Mineral for Biomedical Applications

Hydroxyapatite (HAP) is a well-known medically renowned bioactive material known for its excellent biocompatibility and mechanical stability, but it lacks fast bioactivity. The restricted release of ions from hydroxyapatite encourages the search for a faster bioactive material that could replicate other properties of HAP. A new sol-gel-mediated potentially bioactive glass material that could mimic the structure of HAP but can surpass the performance of HAP bioactively has been formulated in this study. Lefebvre et al. suggested that the silicorhenanite phase with the formula Na2Ca4(PO4)2SiO4 is isostructural to hydroxyapatite; however, data in support of this hypothesis are scant. This study succeeds in developing fast apatite-growth-inducing bioactive glass particles similar to the structure of hydroxyapatite. Also, for the first time, the existence and evolution of two forms of silicorhenanite (alpha- and beta-Na2Ca4(PO4)2SiO4) have been unraveled, and their properties have been explored. The effect of calcination temperature on the phase formation of the biomaterial is notified by looking into the result that heat treatment to 900 degrees C resulted in alpha-Na2Ca4(PO4)2SiO4 (Sili 900) and 1000 degrees C yielded beta-Na2Ca4(PO4)2SiO4 (Sili 1000). This study conveys a new finding that the hydroxyapatite is isostructural to beta-Na2Ca4(PO4)2SiO4 but not to alpha-Na2Ca4(PO4)2SiO4. Raman spectroscopic analysis proved this structural similarity of Sili 1000 and c-HAP, with relative spectra possessing phosphate bands and the irrelevance of Sili 900 to Sili 1000 and c-HAP. The in vitro MTT assay using NIH 3T3 fibroblasts and in vivo wound healing study confirm the enhanced bioactivity and compatibility of Sili 900 and Sili 1000 compared to c-HAP, favored by the presence of a silica matrix and semicrystallinity. pH analysis proved the rapid ionic leaching out from Sili 900 and Sili 1000 and the faster reactivity of Sili 1000 with the fluid. This rapid burst of ions enhances the clotting ability of the Sili 1000 bioactive material and can be a good ibuprofen drug carrier, which is a potential challenger to hydroxyapatite.