Synthesis, characterization, drug loading and in-vitro bioactivity studies of rice husk derived SiO2–P2O5–MgO–CaO–SrO bio-active glasses

Eco-friendly synthesis of mesoporous bioactive glass ceramics and functionalization for drug delivery and hard tissue engineering applications

Hard tissue regenerative mesoporous bioactive glass (MBG) has traditionally been synthesized using costly and toxic alkoxysilane agents and harsh conditions. In this study, MBG was synthesized using the cheaper reagent SiO2by using a co-precipitation approach. The surface properties of MBG ceramic were tailored by functionalizing with amino and carboxylic groups, aiming to develop an efficient drug delivery system for treating bone infections occurring during or after reconstruction surgeries. The amino groups were introduced through a salinization reaction, while the carboxylate groups were added via a chain elongation reaction. The MBG, MBG-NH2, and MBG-NH-COOH were analyzed by using various techniques: x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy and energy-dispersive x-ray spectroscopy. The XRD results confirmed the successful preparation of MBG, and the FTIR results indicated successful functionalization. BET analysis revealed that the prepared samples were mesoporous, and functionalization tuned their surface area and surface properties. Cefixime, an antibiotic, was loaded onto MBG, MBG-NH2, and MBG-NH-COOH to test their drug-carrying capacity. Comparatively, MBG-NH-COOH showed good drug loading and sustained release behavior. The release of the drug followed the Fickian diffusion mechanism. All prepared samples displayed favorable biocompatibility at higher concentration in the Alamar blue assay with MC3T3 cells and exhibited the good potential for hard tissue regeneration, as carbonated hydroxyapatite formed on their surfaces in simulated body fluid.