Research On Preparation Of Bioactive And Biomimetic Micro-Nano Structure On Titanium-Based Artificial Bone Surface

Titanium alloy material which have good mechanical properties and biocompatibility has been widely used in the field of arti-ficial bone grafting.Being biologically inert,titanium alloy material are difficult to form a stable and reliable biological bond with the bone tissue after being implanted into the human body,however,which will cause inflammation around the implant and even the implant falling off and implantation failure ultimately.Therefore,improving the binding capacity of titanium alloy material to bone tissue has become a hot spot in the field of implants.In order to improve the bonding strength between the implant and the bone tissue,a hexagonal micro-nano composite structure resembling the skin shape of a tree frog foot on a titanium alloy surface is designed in this topic,which is based on the principle of bionics and combined with tree frog foot skin with adhesive characteristics.Fiber laser and chemical treatment,fiber laser and femtosecond laser processing are used in this topic to prepare the micro-nano composite structure,and the biological activities of different surface microstructures are studied by immersion experiments in vitro simulated body fluid.Not only that,a calcium-plated calcium titanate coating is prepared on the surface of the titanium alloy artificial bone by laser cladding to further enhance the biological activity.By rsearching on the design,manufacture and biological activity of the biomimetic micro-nanostructure,the following conclusions have been obtained:?1?Through the analysis of the artificial bone structure and the skin morphology of the tree frog's foot,the hexagonal micro-nano composite structure is designed,in which the micro-hexagon side length is 150³00?m,the inter-hexagon groove width is 100?m and nanometer size is 10¹50nm.?2?The relationship between power,velocity and pulse frequency and micro-groove morphology and depth is obtained by studying the influence parameters of titanium alloy surface on fiber laser.According to the designed trench size requirements,power P=14W and speed V=0.2m/min,pulse frequency f=1000Hz are selected for processing of the micro-hexagonal structure.?3?The nanoscale structure is constructed by chemical method and femtosecond laser processing method,of which the surface is characterized and analyzed by scanning electron microscope,ultra depth of field microscope and X-ray diffractometer.The results show that the multiple acid etching method can effectively remove the recast layer produced by fiber laser processing and form nanostructures on the micro hexagonal structure,and the alkali heat and acid-base heat method can form titanate layer and stable on the surface of titanium alloy and the surface porous structure generates a nano-scale structure on the micron-scale structure,and that the femtosecond laser processing method can prepare a nano-structure with regular morphology on the surface of the titanium alloy to obtain a micro-nano combined structure.?4?The surface wettability of different micro-nanostructures is analyzed by contact angle experiment.The results show that the micro-nano composite structure constructed by acid-base thermal method has the smallest contact angle of 20.9°²5.9°.The structure has the best wettability and the highest surface energy.?5?The biological activities of different micro-nanostructures are evaluated by simulated body fluid immersion experiments.The results show that the micro-nano-structured micro-nano-composite structure has the highest mass gain ratio of 2.001%².93%.The structure is beneficial to hydroxyapatite deposition and has good biological activity.?6?Among the linear coatings prepared by the laser cladding method,the immersion method has a good processing effec.The surface of the sample is most CaTiO₃,and the prepared coating has the best effect,when the hydroxyapatite powder?unit:g?and deionized water?unit:mL?are mixed at a ratio of 1:5,and the apatite aqueous solution is higher than the processing plane by 0.08mm and the surface of the titanium alloy is 1mm away from the laser focus.This topic solves the problem of weak bonding between implant and bone tissue by constructing a hexagonal micro-nano composite structure and a calcium titanate coating on the surface of the titanium alloy.The research not only lays a foundation for improving the biological activity of titanium alloy surface,but also lays a theoretical foundation for the combination of bionics and implanted bones,which is conducive to improving the success rate of bone implant and the happy life of people.