| At present,the global aging problem continues to intensify,the occurence of bone defects and the number of repairs of bones have also continued to increase,making artificial bone repair materials widely concerned.The most widely used artificial bone substitute materials in clinical are inert biological materials represented by titanium and its alloy materials,but they are limited in clinical applications due to lack of biological activity.The commonly used and promising solution is to prepare TiO2 coatings on titanium alloy surface in situ,and then the living elements such as Ca and P were introduced to construct the active coating.However,the growth of new bone induced by the active coating was very slow and the recovery period was very long.The confirmed piezoelectric characteristics of bones provide a new direction for bone repair materials,which has good biocompatibility,promoting the adhesion and proliferation of osteoblasts,inducing the formation of new bones and can shorten bone recovery cycle.Therefore,in this paper,the TiO2 nanotube coating was prepared in situ on the surface of titanium by anodizing,and the BaTiO3 coating with piezoelectric properties was constructed on the surface in combination with the sol-gel method,and studied the influence of coating composition,morphology,structure and biological properties,clarified the mechanism of piezoelectric effect on surface mineralization,and the mechanism of nanotube structure drug sustained release.In addition,this paper explored the role of bio-piezoelectric coating in osseointegration,provided basic data for the clinical research of surface-modified titanium and its alloy implants experimentally.The main research results obtained are as follows:(1)The process parameters of TiO2 nanotube layer prepared on the surface of titanium by anodizing method are optimized.The results show that when the anodizing voltage is 60V,the secondary anodizing time is 30min,and the concentration of ammonium fluoride solution is 0.5wt.%.At this time,the pore size and tube length of the obtained TiO2 nanotube layer are moderate,the structure is clear,dense and ordered,the film layer has better binding force and better wetting performance.(2)BaTiO3 coating was constructed on the surface of TiO2 nanotube layer by sol-impregnation method.When annealing temperature is 750℃,the phase is pure barium titanate.With the increase of the rotational speed of sol-spin coating,the phase composition is unchanged,the BaTiO3 particles on the surface are unevenly distributed,the thickness of the coating is reduced,the roughness is increased,the binding force and wettability are deteriorated,the corrosion potential is reduced,the corrosion resistance is weakened,and the best sol spin coating speed is 1000r/min.(3)Through the in vitro simulated immersion experiment,on the 7th day of SBF immersion,a large amount of granular apatite deposits appeared on the surface of the TiO2 nanotube-BaTiO3 coating after polarization,the wettability of the coating was further improved,and the nanotube structure has a significant slow-release effect on the release of drugs such as ALN and GS,which can effectively prolong the drug release time and has excellent antibacterial properties. |
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