Influence of phosphate precursors on the structure, crystallization behaviour and bioactivity of sol–gel derived 45S5 bioglass
Obtaining bioglass composition 45S5® in completely amorphous form without crystalline inclusion by the sol–gel route has remained a challenge so far. Here, we demonstrate that with appropriate phosphate precursor and by controlling the polymerization and gelation reactions by adjusting the pH of the reactants, one can overcome this challenge. As-synthesized glass was heat treated to understand the devitrification behaviour of the sol–gel derived glass and to obtain bioglass–ceramics. As-synthesized and heat treated glasses were characterized using powder X-ray diffraction, transmission electron microscope, differential scanning calorimeter and differential thermal analyzer. For assessing the in vitro bioactivity of sol–gel derived glass and glass–ceramic powders, we tested the apatite forming ability on their surface upon immersion in simulated body fluid. Properties of sol-derived 45S5 glass are then compared with the bulk counterpart obtained by conventional melt quenching method. This study reveals a procedure to prepare completely amorphous sol–gel derived 45S5 glass which can be used as a bioactive material for bone implant, tooth coating, bone tissue engineering and drug delivery applications.