Functional Modification Of Medical Titanium Alloy Surface Based On The Structure Of Zinc Oxide

A bone implant should act as a scaffold to support the formation of new bone,blood vessels and soft tissues,and consequently form a bridge between the existing bone and the graft material to favor the reconstruction of damaged bone tissues.Titanium makes a good scaffold because it can satisfy many of the aforementioned demands.For example,titanium is biocompatible,enhances ingrowth of bone and vascular tissues,possesses antibacterial properties,and delivers good osteoconductive performance.Due to the bacterial colonization of the surface of implanted materials,a well-known problem of bone implants is bacterial infection and the subsequent complications for orthopedic surgery,which often leads to implant failure,prolonging the period and raising the costs of hospitalization,and sometimes even resulting in the patient's death.Therefore,the perfect bone implant should not only be biocompatible,easy to manipulate,mechanicompatible with bone tissues and readily available as well as resorbable or biodegradable in the long term,but should also inhibit the growth of pathogens.Nanostructured materials play a fundamental role in orthopedic research because natural bone has a structural hierarchy on the nanometer scale and is composed of nanostructured collagen fibrils and apatite nanocrystals.Hence,incorporation of nano-topographical features that mimic the organization ofbone is a burgeoning research area in tissue engineering,and titanium based nanomaterials have been used as hierarchical structures in scaffolds to foster bone regeneration.Due to their good thermostability,marked antimicrobial activity and low cost,ZnO nanostructures are becoming one of the most promising inorganic antimicrobial materials,particularly for tissue regeneration.Based on hereinbefore problems,The basic contents of the thesis are as follows:1.Synthesis ofAg/ZnO nano rods array on Biomedical TitaniumThe ZnO nano rods were successfully made by the combination of spin coating and hydrothermal approach,and the small Ag nanoparticles were sputtering to the surface of ZnO nanorods.The effect of Ag doping on ZnO nanorods against Staphylococcus aureus and Escherichia coli is discussed.It was found that the aligned ZnO nanorod arrays on the surface of biomedical titanium vertically.And the Ag namoparticles covered on the surface of ZnO nanorods.In our study,ZnO nanorod have a good antibacterial activity,and the antibacterial activity increased with add of silver.2.Constructing TiO2 nanotube arrays on titanium surfaceThrough adjusting the reaction parameters of the anodic oxidation,the TiO2 nanotubes on titanium has been achieved.Experiment parameters,such as the anodic oxidation reaction time,voltage,temperature and electrolyte concentration of fluoride ions,will affect the morphology of TiO2 nanotube.Controlling the morphology of TiO2 nanotubes will helpful for the subsequent drug loading experiments.In this paper,the formation mechanism of TiO2 nanotubes by the electrochemical anodic oxidation was preliminarily discussed.The instantaneous current and time relation curve showed that the formation process of nanotube could be divided into three stages,namely,the formation stage of high resistance TiO2 block layer,the formation stage of pits and holes on the surface of titanium,electrochemical oxidation and electrochemical corrosion achieve a dynamic equilibrium phase.3.pH Controlled Drug Release from TiO2 nanotubes via Intracelluar Dissolution of Folic acid-ZnO QDsFolic acid-ZnO QDs were synthesized by attaching folic acid onto the ZnO-NH2 QDs,and then the ZnO-FA solution were pipetted onto the drug loaded titania nanotubes.So drug release could be controlled by the different pH values.In our study,the vancomycin have good antibacterial activity to Staphylococcus aureus.With the gradual increase of the pH value,the drug release rate of the drug can be regulated.