Dissolution and in vitro bioactive properties of BaO added Na₂O–CaO–P₂O₅ glasses

Na₂O–CaO–P₂O₅ glasses with different additions of BaO were subjected to dissolution tests in deionised water and in vitro bioactivity tests in phosphate buffer saline (PBS) as well as Hank's balanced salt (HBS) solution. Phosphate glasses of composition (26–x)Na₂O–xBaO–29CaO–45P₂O₅ (x=0, 5, 10, 15 mol%) were prepared by melt-quenching. The dissolution characteristics of these glasses were studied in deionised water under static conditions based on BaO composition. The dissolution rate of the glasses in deionised water decreased with BaO content. The in vitro bioactivity tests were carried out in PBS and HBSS for 28 days under static conditions. The bioactivity of the samples was verified by XRD, SEM/EDS and FTIR techniques. Hydroxyapatite phases were formed on all the glass samples within seven days of immersion in HBSS and the bioactivity was found to improve with BaO content. The glasses without BaO and with 15 mol% BaO showed the hydroxyapatite phases within the immersion of 14 days in PBS whereas the glasses with 5 and 10 mol% BaO showed formation of amorphous hydroxyapatite phases.