Enhancement of in vitro bioactivity and cytotoxicity of mesoporous bioactive glass through template-free spray drying synthesis

Silica-based mesoporous bioactive glass (MBG) has gained widespread attention owing to its excellent bioactivity, biodegradability, and non-toxic nature. Due to these superior properties, MBG has found applications in various fields, such as skeletal and dental reconstruction. Yet, common pore-forming agents such as long-chain or tri-block polymers were used as soft templates, which could result in residual carbon contamination and lead to decreases in biological properties. Thus, in this work, we proposed the template-free synthesis of MBG specimens via the spray drying method employing H₂O₂ as a novel pore-forming agent. Since H₂O₂ does not contain any carboxyl groups, contamination from residual carbon can be minimized, making it suitable for the preparation of high-purity MBG. The phase information, particle morphology, and specific surface area were examined using X-ray diffraction, scanning electron microscopy, and nitrogen adsorption and desorption. Additionally, in vitro bioactivity was evaluated according to ISO protocol to assess the formation of hydroxyapatite. Furthermore, in vitro cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that MBG treated with 30 vol% of H₂O₂ achieved a comparable specific surface area to that of the P123-treated specimen, while demonstrating enhanced bioactivity and retaining non-toxic properties.