Bioglass and antibiotic-loaded mesoporous silica composite pellets as a local antibiotic delivery system for the prevention of postoperative bone infections

Abstract Postoperative bone infections remain a significant challenge in regenerative medicine, requiring innovative prevention approaches that combine antimicrobial activity with bone regeneration. This study presents a novel bifunctional local antibiotic delivery system in the form of spherical granules (pellets) designed for prolonged antibiotic release and bone tissue regeneration. The pellets were manufactured by combining ciprofloxacin-loaded or vancomycin-loaded mesoporous silica together with bioactive glass 83S2 (BG83S2) obtained via rapid, one-pot sol–gel synthesis. The BG83S2 demonstrated satisfactory physicochemical properties and apatite-forming ability comparable to commercially available bioactive glasses 45S and 85S. The resulting pellets exhibited progressive apatite layer formation in simulated body fluid over 28 days. Drug release profiles showed biphasic antibiotic release, providing an initial loading dose within 24 h, followed by maintenance doses for the next 5 days. Antimicrobial assay against Staphylococcus aureus and Staphylococcus epidermidis confirmed effective antimicrobial activity of pellets. The cytotoxicity studies towards the human fetal osteoblast cell line (hFOB1.19) demonstrated satisfactory cytocompatibility of pellets and osteoblast attachment onto the pellet surface. The proposed pellets can be considered a promising multifunctional local antibiotic delivery system for preventing postoperative bone infections and supporting bone regeneration.