Study On Antibacterial And Osteogenic Activity Of New Titanium Nanotube Composite Coating

Objectives: The implant associated infection and insufficient osseointegration are the main reasons for the current clinical failure of intraosseous implants.The purpose of this experiment is to design and prepare a novel titanium nanotube composite coating,to detect and analyze its morphological characterization,physical and chemical properties,and to evaluate its antibacterial effect,biocompatibility and osteogenic activity,and related mechanism,so as to provide the basis for further research and application in the future.Methods: A novel titanium nanotube composite coating was fabricated by electrodeposition method.The properties of coatings were detected by SEM,EDS,XRD,XPS and cross-cut tape test.Ion release was detected by ICP-AES.Antibacterial properties were detected by inhibition zone experiment,plate counting method,SEM and fluorescent staining.The biocompatibility of the coatings on OVX-BMSCs was studied by CCK8?fluorescence staining,et al.The related mechanisms of osteogenic induction of coatings were investigated by ALP,ELISA,qRT-PCR,western blot,IP,and plasmid transfection.RESULTS:(1)A novel titanium nanotube composite coating prepared by anodization and electrodeposition techniques,the inner layer is a titanium nanotube dopped with silver nanoparticles,and the outer layer is a composite coating of chitosan/gelatin matrix mixed with silver nanoparticles and zinc oxide.The composite coating(TNTs/Ag-Cs/Gel/Ag/ZnO)has good adhesion strength.(2)The new composite coating has better antibacterial effect against Staphylococcus aureus(planktonic bacteria and adherent bacteria),compared with titanium nanotubes coating and titanium nanotubes with silver coating.It is more favorable for adhesion and proliferation of OVX-BMSCs,higher expression of mRNA and proteins of ALP,RUNX2 and USP9 X.The mRNA expression level of ?-catenin did not increase much,but the protein expression level of ?-catenin is significantly increased.(3)After up-regulating the mRNA expression of USP9 X,the protein expression of ?-catenin and ALP activity on the surface of the new composite coating increased significantly;while down-regulating USP9 X,it decreased significantly.After treatment of OVX-BMSCs on the surface of the new composite coating with TNF-? recombinant protein,the protein expression level of ?-catenin and ALP activity were significantly decreased.However,there was no significant change in the protein expression of USP9 X and ALP activity after the addition of TNF-? recombinant protein to stem cells overexpressing USP9 X.Conclusion: The new composite coating has good antibacterial effect and biocompatibility,and has better osteogenic induction effect on OVX-BMSCs,which is related to TNF-?/USP9X/?-catenin signaling pathway.