Sol-gel synthesis of borate-based 13-93B3 bioactive glass powders for biomedical applications

In this study, borate-based 13–93B3 bioactive glass powders were synthesised through a sol-gel method using tributyl borate as the boron precursor. Any gel formation was not observed in the glass sol during processing and upon the solvent evaporation, a gel-like layer was obtained. Calcinations were performed between 450 °C and 625 °C in air atmosphere to decompose the nitrates leading to the formation of metal oxides in the glass network. Results showed that use of high calcination temperatures to remove the nitrates from precursor materials caused the formation of partially crystalline structures. In vitro mineralisation experiments revealed that synthesised powders calcined at 550 °C converted to hydroxyapatite phase after immersion in simulated body fluid for 1 day. It was concluded that sol-gel- derived 13–93B3 glass powders have enhanced bioactivity and can be an alternative to conventional melt-derived borate-based bioactive glasses synthesised at much higher temperatures.