Optimization of the sol–gel synthesis parameters on Zn–Cu–Co-doped silicate-based bioactive glass for tissue repair

Sol–gel synthesis parameters can significantly influence bioactive glass’s structure, dissolution rates, and biocompatibility. For this study, various drying times and calcining temperatures were explored for a Zinc (Zn²⁺), Copper (Cu²⁺), and Cobalt (Co²⁺) doped silicate-based sol–gel bioactive glass composition. Surface area measurements showed an increase in the particle’s surface area with decreased calcining temperature, whereas the particle size decreased with longer drying time and higher calcining temperature. The micropore area and volume showed an inverse relationship to the reduced particle size, with the microporosity increasing as the drying time was extended with the calcining temperature below the glasses’ transition temperature (560–586 °C). A Kilchoanite (Ca₃(Si₂O₇)) crystalline phase was present in each sample, and with increased calcining temperature above the T_g of the glasses, the degree of crystallinity increased. A drying time of 72 hrs with a calcining temperature of 450 °C showed an enhanced surface area (120 m²/g) with smaller average particle size (0.43 µm), increased microporosity, ion release rates within toxicity and pH limits, and growth inhibition for both gram-positive (S. aureus) and gram-negative (E. coli) bacteria.