Preparation Of Zinc Substituted Hydroxyapatite Composite Scaffold And Antibacterial And Anti-inflammatory

As a major inorganic component of natural bone, synthetic hydroxyapatite(HA) is widely used as a compatible bone graft material. HA can be fabricated into scaffolds with compatible polymers, such as polyvinyl alcohol(PVA) and gelatin. PVA is non-toxic, hydrophilic and has good adhesion properties. Gelatin has homology with collagen. In this study, zinc substituted hydroxyapatite(ZnHA) was made into scaffolds with PVA and gelatin.The HA and ZnHA powders with different Zn/Ca mole ratios were prepared by co-precipitation. The powder was characterized by X-ray diffraction(XRD) analysis, and transmission electron microscopy(TEM). The results showed that, with the increase of Zn/Ca mole ratios, the shape of particles changed from plate-like shape to rod-like shape. The sizes of crystal became smaller, which suggested that the zinc doping might inhibit the growth of HA crystal. In addition, the antibacterial property of ZnHA powders was proved by antibacterial experiments.The ZnHA/HA composite scaffolds were fabricated by freeze-drying process. The porosity, surface topology, function groups, thermal stability, compress strength and apatite formation in vitro of the scaffolds were investigated. The porosity was above 85%, and the diameter of pores was from 40 ?m to 200 ?m. The compress strength reached 0.2 MPa. It was concluded that the composite scaffold has uniform and steady structure.The rat calvarial defect animal model was used to investigate the scaffold through histological evaluation 12 weeks postoperatively. It was found that more inflammatory cells were observed in the Zn HA scaffolds group by histological evaluation.In conclusion, the incorporation of ZnHA into bone graft scaffolds could bring additional values such as antibacterial and inflammatory stimulation.