Study On The Nano-hydroxyapatite-Vancomycin Drug-loaded Coating On The Surface Of Titanium/Titanium Dioxide Nanotubes Constructed By Electrodeposition

Research objective: Implant infection is a major cause that causes implant failure.Constructing a drug-loaded coating on the surface of an implant with sustained release and anti-infection functions has broad clinical application prospects.Titanium dioxide nanotubes and hydroxyapatite have been deeply studied for their good biological activity,but the antibacterial properties of the two materials are not good enough.Therefore,by integrating the two materials,constructing a composite coating which has both good biological activity and antibacterial properties is a better research direction with practical clinical significance.In this study,the prepared nanohydroxyapatite and titanium dioxide nanotubes were integrated by the method of electrophoretic chemical deposition,and then the composite coating was used as a drug carrier and loaded with vancomycin hydrochloride.It is expected to construct a composite coating material that has both antibacterial properties,a good biological activity and without potential cytotoxicity.Research methods: In this study,a two-step anodic oxidation method was used to construct titanium dioxide nanotubes on the surface of metal titanium,and nanohydroxyapatite powder was synthesized by hydrothermal method.The prepared nanohydroxyapatite was supported on the surface of titanium dioxide nanotubes by electrophoretic deposition in an alcohol solution.Thus,a composite coating structure of titanium dioxide nanotubes/hydroxyapatite on the titanium-based metal surface is obtained.Subsequently,the composite coating is used as a drug-bearing platform,and vancomycin hydrochloride is loaded by physical adsorption and finally obtain a drug-loaded composite coating.The in vitro drug release experiment of the composite coating was used to explore its sustained-release effect.The prepared composite coating was co-cultured with Staphylococcus aureus to evaluate its antibacterial performance,and the composite coating was co-cultured with human osteoblasts to evaluate its potential cytotoxicity.Research results: 1.Titanium dioxide nanotube structure on titanium surface was successfully constructed by two-step anodizing method.Scanning electron microscopy results showed that the diameter of the nanotubes was about 150 nm,which appeared as a regularly arranged tubular structure.Nano-sized hydroxyapatite powder was constructed by hydrothermal method.And then by the method of electrophoretic chemical deposition,a uniform and dense hydroxyapatite coating was constructed on the surface of titanium dioxide nanotubes;and vancomycin hydrochloride was loaded into the composite coating in a dropwise manner.The composition analysis results of the coating showed that the surface composition of the coating constructed by electrophoretic chemistry has not changed,and loading of the drug does not affected the composition of the coating.2.The result of in vitro drug sustained-release studies show: Titanium dioxide nanotube/hydroxyapatite composite drug-loaded coating,which has longer drug release efficiency than simple titanium dioxide nanotubes and hydroxyapatite coating on bare titanium surface.The results show that the drug release time of the composite drug-loaded coating exceeds 150 hours.3.Antibacterial zone test results show that the compound drug-loaded coating has a good antibacterial effect,and the average diameter of the antibacterial zone is greater than 7mm;the antibacterial rate;The antibacterial rate test results show that after co-culturing with Staphylococcus aureus for 24 hours,the drugloaded compound coating has an obvious bacteriostatic effect.There was no bacterial colony growth on the gradient dilution plate.The bacteriostatic rate reached 100%,and the bacteriostatic effect was obvious.4.Cytotoxicity test results of drug-loaded coatings showed that there were significant differences between the concentrations of the extract groups(p <0.05).The relative activities of the cells in the extract groups were greater than 70% when they were co-cultured for 1 day,3 days,and 5 days.The results of cell adhesion on the coating surface showed that the cells could normally adhere and grow on the surface of the drug-loaded coating,the ratio of cytoplasm and cytoplasm was normal,and the cytoskeleton was intact,and there was no significant difference between the control group and the blank group.The drug-loaded coating has no obvious toxicity and inhibitory effect on cell growth.Research conclusion: 1.Hydroxyapatite composite coating was constructed on the surface of titanium dioxide nanotubes by electrophoretic chemical deposition,and the drug was effectively loaded by physical adsorption.2.The compound drug-loaded coating has better drug sustained-release performance.3.The compound drug-loaded coating has good antibacterial efficacy in vitro and has no obvious toxic and inhibition effects on osteoblasts.