Osteogenic Effect Of TiO₂ Nanotube BMP2/BMP7 Composite Layer On Titanium Implant Surface

Infection treated by human endogenous implantation is the most common complication in the process of clinical treatment,especially the infection after intraosseous dental implant,not only slows down the wound healing of patients,but also increases the risk of failure of implant surgery,resulting in a waste of medical materials.the endogenous infection in dental implant surgery is generally caused by the adhesion and proliferation of bacteria,after the formation of biofilm,the performance of proliferation is greatly improved,even up to 1000 times that in the free state of bacteria.therefore,avoiding the adhesion of bacteria on the surface of endogenous implants is the key to the success of human implant surgery,which can effectively prevent and control the risk of infection of endogenous implants.titanium alloy is widely used in clinic as an endogenous implant because of its good physical and chemical properties and high biocompatibility.Purposes:the main idea of this study is to prepare Ti O₂nanotube on TC4 titanium surface by various modification methods,increase the specific surface area of the material,and use the porous structure of the surface to coat with bioactive substances to increase the osteogenesis performance of the materia.in this paper,based on titanium,the osteogenesis induced by the implant material was improved from the perspective of surface modification of titanium material and promotion of osteogenesis by loading growth factors,and the cytocompatibility and osteogenesis performance of the implant material were studied in vitro with mouse bone marrow mesenchymal stem cells as a model.Methods1.In this study,the morphology of Ti O₂nanotubes was prepared on the surface of TC4 titanium by two-step anodization,and BMP2 and BMP2/7were grafted and coupled with polydopamine as carrier by chemical pre-modification to prepare Ti O₂nanotubes-polydopamine-BMP2 and Ti O₂nanotubes-polydopamine-BMP2/7composite layers,respectively.the surface morphology and element composition were characterized by field emission electron microscope?SEM?,X-ray photoelectron spectroscopy?XPS?and contact angle measurement.2.The prepared composite layer samples and mouse bone marrow mesenchymal stem cells were co-cultured in vitro to simulate the complex internal environment of human body,in order to obtain objective experiment data.using scanning electron microscope to observe the morphology.1?3?5 days MTT method to detect cell adhesion and proliferation on the surface of the composite material.cells and materials were co-cultured for 5?7?11days to detect alkaline phosphatase activity test?ALP?to study the effect of BMP2/7 loaded Ti O₂nanotube materials on the proliferation and differentiation of bone marrow mesenchymal stem cells.Results1.Scanning electron microscopy?SEM?observation showed that Ti O₂nanotubes and various composite coatings have been successfully constructed on the surface of TC4 titanium.X-ray spectroscopy element analysis indicated that BMP2/7 was successfully loaded on the surface of Ti O₂nanotubes.contact angle and surface energy analysis showed that the loading the BMP2 and BMP2/7 experimental groups have better hydrophobicity,which achieved the purpose.2.Scanning electron microscope observation showed that the surface cells of Ti O₂nanotubes modified with BMP2/7 adhered more than the control group.MTT results showed that the cell adhesion and proliferation of the experimental group was significantly higher than that of the control group after 3 days?P<0.01?.pairwise comparison of SNK method showed that there were also significant differences between the groups?P<0.05?.after 5 days,the alkaline phosphatase activity of the experimental group was showed that both are higher than the control group,and there are statistical differences between the experimental groups?P<0.01?.the pairwise comparison of the SNK method showed that the experimental groups were statistically significant with each other?P<0.05?,indicated that compared with the control group,the experimental group can significantly increase the osteogenic performance.ConclusionIn this study,after a series of experiments,Ti O₂nanotube/PDOP/BMP2/7composite coating was prepared on the surface of the TC4 titanium substrate,which effectively increased the specific surface area of the material and increased the adsorption performance of the material.it can be used as a good biologically active substance carrier.the comparison shows that the Ti O₂nanotube material loaded with BMP2/7 can significantly improve the osteogenesis effect of bone marrow mesenchymal stem cells.it is an effective method for surface modification of endogenous implants and has good medical application prospects.