Construction and properties of an osteogenic-antibacterial functionalised drug delivery system based on hydroxyapatite microspheres

Pure hydroxyapatite (HA) has attracted much attention in the field of bone repair materials due to its strong potential for bioavailability, but its low osteogenic activity and non-bacterial inhibition limits its further application in this field. Therefore, in this study, strontium (Sr)-doped hydroxyapatite (HA-Sr) microspheres with a high specific surface area were prepared without adding a templating agent. On this basis, berberine hydro-chloride (BBH), a Traditional Chinese antimicrobial agent with excellent antibacterial ability, was loaded to overcome traditional limitations and construct a material with good osteogenic activity and antibacterial ca-pacity. A series of characterization results showed the doping of Sr did not affect the physical phase and morphology of HA but altered its chemical composition and crystallinity, and HA-Sr microspheres had good microscopic morphology and ion retardation, which laid the foundation for the subsequent improvement of the integrated capacity. In vitro cell experiments showed that Sr ions could significantly promote the differentiation of rBMSCs at a range of doping concentrations. In this study, the optimal doping concentration of 3% was systematically screened by cell proliferation assay, alkaline phosphatase staining and alizarin red staining in a small concentration range (1-7%). Subsequently, BBH was loaded with 3% Sr ion-doped HA microspheres to construct the drug loading model. And the sustained release test and antibacterial test further proved that its antibacterial performance was enhanced. The combined results of these experiments indicated that this material was successfully constructed with good osteogenic activity and antibacterial property, and its biological property was greatly improved.