In vitro bactericidal and drug release properties of vancomycin-amino surface functionalized bioactive glass nanoparticles

Bioactive glass has been used clinically in bone repair applications for bone grafting because of its prominent physiochemical and osteogenic properties. Various attempts have been made to enhance bioactive glass efficiency in combination with other biomaterials such as antibiotics and growth factors. In present study, we developed a modification of bioactive glass nanoparticles that insured long term antibacterial effect. Bioactive glass nanoparticles (BGNs) were functionalized with (3-Aminopropyl) triethoxysilane (APTS), then vancomycin (VAN) was immobilized onto BGNs-APTS via EDC/NHS cross-linking process. Another study group namely BGNsVAN was synthesized as a control group without any cross-linking process. The nanoparticles were analyzed by FTIR, Zetasizer, XRD, and SEM instruments. FTIR and Zetasizer results confirmed the functionalization and immobilization processes. Drug release was evaluated by UV-Vis spectroscopy in a phosphate buffered saline (PBS) solution. BGNs-APTS-VAN had a long term release profile with a different release kinetics formulation. The release profile of vancomycin didn't fit with common analytical models. A new mathematical model was suggested. Minimum bactericidal concentration (MBC) of nanoparticles against MRSA bacteria was obtained at 1.25 mg/mL. Vancomycin burst release in BGNs-VAN made a delay in the ALP enzyme secretion from MC3T3 cells, while in BGNs-APTS-VAN, the burst release decreased and consequently the delay in ALP enzyme secretion decreased.