Surface Functionalization And Properties Of Biomedical Titanium Based On Polymer

Due to the acceleration of population aging,the increasement of trauma in traffic accidents,industrial accidents and natural disasters,the variability of disease,the enhancement of people's health consciousness,the promotion of technological innovation ability,the social demand for biomedical materials is growing.Because elastic modulus and mechanical strength of biomedical titanium and its alloys are similar to human hard tissue,and biomedical titanium and its alloys have good fatigue strength,easy processing,corrosion resistance,non-toxic and excellent biocompatibility,etc.,they are widely used in cardiovascular materials,hard tissue replacement materials,osteosynthesis materials and other medical applications.However,the initial biomedical titanium and its alloys belonging to biologically inert materials,as the implant materials,affect the body's host response and for a long time can cause the formation of thrombus which lead to the failure of the implant surgery.At the same time,because the surgery can not completely avoid infection,bacterial infection is a major threat in clinical medical surgery.To improve the biologically inert property and obtain simultaneously both the biological activity and antibacterial properties of biomedical titanium and its alloys,biomedical titanium and its alloys are generally modified by surface functionalization.Because polymers could flexibility to introduce various functional groups,they could control the properties of biomaterials such as chemical stability,wettability,corrosion resistance,biocompatibility and so on.polymers are used in surface functionalization of biomedical titanium and its alloys.Based on the above issues,this paper is mostly about that the surface of biomedical titanium and its alloys is functionalized by fixing polymer-based coatings.Baed on chitosan,a kind of polymer which can promote cell adhesion and antibacterial,inorganic matters(hydroxyapatite and silver-containing material)are added to prepare chitosan-silver/hydroxyapatite composite on the surface of the biomedical titanium and its alloys by electrochemical deposition method to make titanium metal surface with both bioactive and antibacterial properties.The polymer brush of poly(2-hydroxyethyl methacrylate)are prepared on the surface of biomedical titanium via atom transfer radical polymerization to resist cell adhesion and improve corrosion resistance for the use in medical applications like pegs which are need again to remove from the body.Another method is utilized,namely layer-by-layer technique.At first,biomedical titanium is soaked in dopamine solution,and then immobilize hyaluronic acid,and finally chitosan is deposited onto the surface of titanium by spin coating to improve cell adhesion.The basic contents of this thesis are as follows:1.In order to deposite materials onto the surface of pure titanium,pure titanium materials are treated by alkali heat reaction to obtain a titanium metal surface with pores,and then chitosan-silver/hydroxyapatite composite are prepared under constant current condition by electrochemical deposition method.The results show that the antibacterial property and cell adhesion of the modified titanium with composite are better than pure titanium.2.By understanding the reaction mechanism of atom transfer radical polymerization and using dopamine as the active bridge between the titanium surface and the polymer,the poly(2-hydroxyethyl methacrylate)coating is grafted from the surface of titanium layer.The test results show that compared with the titanium surface,the hydrophilic ability,corrosion resistance property of the titanium surface with polymer brushes are better,while their cell adhesion is worse.3.Polymer hyaluronic acid and chitosan are fixed onto the surface of titanium by layer-by-layer technique.Firstly,titanium materials are soaked in dopamine solution to let the carboxyl group of hyaluronic acid react with an amino group on the dopamine,which makes hyaluronic acid graft on the surface of titanium,and finally chitosan is immobilized onto the modified surface of titanium by spin coating.The results reveal that the modified surface of titanium can improve cell adhesion.