Surface Functional Modification And Drug Loading Properties Of Biomedical Titanium Implants

Due to the acceleration of global population aging,osteoporosis and fracture are increasing in clinical practice,plusing traumas caused by natural disasters,such as traffic accidents,occupational injury,making the growing demand for medical implant materials.Because of its elastic modulus close to the human bone,good mechanical properties and biocompatibility,corrosion resistance and simple peocess,biomedical titanium materials are widely used as hard tissue replacement materials,such as artificial joints,dental implants and etc.However,titanium and its alloys belong biologically inert material,after implantation,this material can not form a close bone combination with hard tissue in organism,but just simple mechanical lock with surrounding tissues,easily wrapped by fibrous tissue then isolated from host tissue,in the long run,that will lead to thrombosis and result in failure.In addition,in clinical surgery,the bacterial infection is one of the major common problems,comprehensive sterilization and aseptic still can not avoid the occurrence of postoperative infection.Clinically,the main solution is injected antibiotics,but antibiotic injections have specificity and will produce drug-resistant strains after long-term injection.Therefore,the preparation of implant materials with both biological activity and anti-bacterial properties is an important issue need to be solved urgently.Based on hereinbefore problems,The basic contents of the thesis are as follows:1.Preparation of TiO2 nanotubes/PLGA hybrid porous scaffoldsIn this study,the silane coupling agent(KH550)was grafted on the surface of TiO2 nanotubes,and then reacted with high activity-terminated Poly(lactic acid-glycolic acid)(PLGA),the TiO2 nanotubes bonded through the amide bond grafted onto the surface of PLGA.Energy spectrum analysis showed that the hybrid material dispersed more evenly.Mineralization experiments in SBF and contact angle measurement results showed:TiO2 nanotube/PLGA hybrid scaffold is more conducive to the deposition of calcium and phosphorus layers and improve its surface hydrophilic properties.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.TiO2 nanotubes as drug nanoreservoirs and the related drug release mechanismThe prepared TiO2 nanotube samples immersed in a certain concentration of a model drug(ibuprofen),and then using the spin coating method coated 1,3,5 8,10 layers of biodegradable polymer(PLGA)on its surface,respectively.By controlling the number of PLGA layers,the release rate of the drug can be regulated.When coating 10 PLGA layers,drug release days can be up to 40 days,that provide a strong theoretical basis for clinical.Potentiodynamic polarization curves investigated that TiO2 nanotubes with PLGA coating exhibits relatively good corrosion resistance.