Sol-gel synthesis of nano-bioactive glass 60SiO₂-36CaO-4P₂O₅ (mol.%) without using acid catalysts

Nano-bioactive glass 60SiO₂-36CaO-4P₂O₅ (mol.%) was synthesized by using the sol-gel method without using acid catalysts. Two sol precursors, tetraethyl orthosilicate and triethyl phosphate, were tested for hydrolysis at different temperatures and times. Experimental observation shows that the precursors tetraethyl orthosilicate, triethyl phosphate, and calcium nitrate tetrahydrate were hydrolyzed in the solvent system H₂O/C₂H₅OH (weight ratio of 1/8) at 80 °C. In a hydrothermal reactor, the resulting sol was transformed into a gel, and then the dried gel was transformed into a glass material by heating treatment. Physical-chemical methods such as TG-DSC, XRD, FTIR, BET, and SEM-TEM were used to evaluate synthesized glass. Additionally, the glass material was assessed for its bioactivity in SBF solution (Simulated Body Fluid), and biocompatibility with fibroblast cells (L-929) following the ISO10993-5 standard. Research results show that the glass 60SiO₂-36CaO-4P₂O₅ (mol.%) synthesized in this study is an amorphous material with particle size at the nanoscale, forming a mesoporous structure. The synthesized glass can be bioactive by forming an apatite mineral layer when soaked in SBF solution, and it is biocompatible with L-929 cells.