Enhancing bioactivity, radiopacity, and structural properties of borophosphate glass through barium oxide modification and controlled thermal treatment

Abstract

This study explores the impact of replacing P2O5 and B2O3 with varying amounts of barium oxide (BaO, 0–10 mol%) in borophosphate glasses. The investigation focuses on the structural, bioactivity, and radiopaque properties of the resulting materials. Four glass samples were prepared using a melt-quench technique. Their bioactivity was assessed through immersion in simulated body fluid (SBF) for 28 days. Additionally, a 24-h thermal treatment at 530 °C was employed to induce crystallization and evaluate the bioactivity of the resulting glass-ceramics. Initial X-ray diffraction (XRD) analysis confirmed the amorphous nature of the glasses. Conversely, crystalline phases were identified after the thermal treatment. Increasing BaO content led to higher volumetric density while altering the molar volume and structure as revealed by Fourier-transform infrared spectroscopy (FTIR) analysis. Lower pH values were observed with increasing BaO content, suggesting its influence on controlling the release of ions from the material. Both XRD and FTIR analyses detected the formation of hydroxyapatite (HAp) and fluorapatite (FAp) phases in all samples. Notably, the glass-ceramic containing 10 mol% BaO exhibited the most significant apatite formation. Radiopacity measurements improved with increasing BaO content, indicating potential applications in bone replacement materials due to enhanced visibility in X-ray imaging. Cell viability tests confirmed the non-toxic nature of the samples, with higher BaO content promoting cell proliferation, suggesting potential for tissue regeneration. Overall, these findings suggest promising biomedical applications for all the studied compositions.