Bone Integration-promoting And Antibacterial Properties Of Gallium-doped Titanium Dioxide Coating Modified Titanium Surface

Background: The preparation of orthopedic implants with the function of promoting bone integration and antibacterial is promising in orthopedic applications.The microstructure of titanium dioxide nanotubes can change the surface inertia of titanium metal,increase the biocompatibility of the material surface,induce the differentiation of bone marrow mesenchymal stem cells into osteoblasts,and promote the formation of new bone tissue.Enhance the ability of bone integration.Gallium ion is a relatively new metal antibacterial agent,and can inhibit osteoclast bone resorption in a dose-dependent manner.polydopamine(PDA)is strongly bound to the metal surface,improving the hydrophilicity of the material surface.Methods: Ti O2 nanotubes were prepared on the surface of titanium sheet by anodic oxidation method,and gallium ions were doped with the adhesive properties of PDA.Scanning electron microscopy was used to observe the microstructure of the material surface,X-ray diffractometer and X-ray photoelectron spectroscopy were used to detect the surface composition and analyze the crystal structure,and inductively coupled plasma technology was used to verify the construction of the local release system.Quantitative reverse transcription polymerase chain reaction and western blot assay were used to detect the expression levels of markers for osteogenesis of BMSCs cells and osteoclast differentiation of RAW264.7 cells.The changes of cell morphology during induction were observed by actin-nuclear staining.The bone defect model of SD rats was constructed in vivo,mic-CT and methylene blue-acid fuchsin staining were used to observe the surface new bone.In addition,Staphylococcus aureus and Escherichia coli were used respectively to verify the antibacterial properties of the material surface.Results: EDS,XRD,XPS and other methods have successfully verified that a certain amount of gallium ion is attached to the surface of the material,and a local slow release system has been successfully constructed.PDA and an appropriate amount of gallium ion will not damage the viewing structure of Ti O2 nanotubes,but too much concentration of gallium ion will block the tube port.Molecular biology experiments showed that the multifunctional coating on the surface of the material could effectively promote osteogenic differentiation and inhibit the expression of osteoclast-related genes and proteins.In vivo studies further demonstrated that the material with the multifunctional coating had stronger bone-binding strength.In addition,gallium ion doped specimens also have good antibacterial activity.Conclusions: When Ti O2,PDA and appropriate amount of gallium ion are combined together,the multifunctional coating has many advantages,such as good biocompatibility,promoting bone integration function,antibacterial property and so on,which has potential application in orthopedic implants.