Synthesising lithium-alumina-borate glass-ceramic for potential applications in regenerative bone establishment

Lithium-alumina-borate (LAB) glass-ceramic demonstrates potential materials with physicochemical and cytocompatibility characteristics which needs further investigation in terms of bone regeneration. Borate substitution in the LAB follows the formula in mole percentages (mol.%) of 70 B₂O₃-(30-x) Li₂O-x Al₂O₃. The melt-derived LAB was dried at 60 °C and subjected to thermal analysis, X-ray powder diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy, pH profile analysis and in vitro bioactivity using simulated body fluid (SBF) with biocompatibility assessment towards SaOS-2 human cell line. Thermal analysis confirmed the stability and glass-forming ability of LAB glass-ceramic. The XRD showed peaks corresponding to HA for LA4B and LA6B at 2θ degree, ranging from 20° to 60°, while FTIR showed phosphate peaks of hydroxyapatite overlapping with the borate or alumina peaks for LA4B and LA6B at ∼550 cm^-1 and ∼1100 cm^-1. SEM-EDX results showed that LA4B samples formed better HA than LA6B and LA8B because the former has more phosphorus and calcium deposition in weight percentages on the glass-ceramic surface than the latter. The pH profiles of all the LAB glass-ceramic showed increasing trends until day 7, thereby suggesting potential HA formation. The in vitro ionic release in SBF advocates the role of each element in LAB because of its bioactive and biocompatible characteristics. MTT assays elucidate the potential of LA4B samples to be biocompatible towards the human osteoblast SaOS-2 and a cytocompatibility candidate that merits further biological evaluation, including osteogenic differentiation and in vivo studies, before its suitability for bone regeneration can be established.