In-vitro mineralization of borosilicate glasses and accompanying evolution of porous architecture

Sol-gel process proved to be an effective approach to synthesize borosilicate-based bioactive glasses with significant crystallization induced during devitrification verified by Na₂CaSiO₄ phase. A progressive growth of hydroxyapatite (HA) phase in the size range of 17-26 nm was observed. Fourier transform infra-red (FTIR) spectroscopy suggested the presence non-bridging oxygen (NBO) and BO₃ groups that facilitated rapid ion exchange. While bands at 550-650 cm^-1 (PO₄^3-) and 1524 cm^-1 (CO₃^2-) confirmed the formation of carbonated HA. The porous architecture of bioactive glass facilitated rapid in-vitro mineralization while crystalline bioactive glass improved dimensional stability and controlled degradation which renders it ideal for hard tissue engineering scaffolds where structural integrity is important besides biological functions.