Study On Nanometer Bacteriostatic And Antibacterial Implants

Though implants promotes the development of orthopeadics,it increases the risk of infection.The complication of infection causing by implants is a disaster which leads to much money loss and challenges the decision of orthopeadist on treatment.Superficial bacteriostatic or antibacterial modification of implants becomes a new treatment or prevention for that the infection occurs at the interface between the implants and surrounding tissues and begins from the adhesion of bacterial. Theoretically,The bacteriostatic or antibacterial microenvironment forming after the surface modification reduces the adhesion of bacterial,improving autoimmunity and the antibiotic ability in bacterial-killing.Objective:In order to reduce the infection probability of implants,the problem of bacterial planting and adhesion on the surface,the first step of infection,is the first one to solve.Analyzing the action mechanism of bacterial adhesion to different hydrophilic and hydrophobic surfaces of implants,a design proposal is raised here to decrease the surface hydrophilicity and turn it into super-hydrophobicity,and the result of bacteriostasis was verified also. Meanwhile,a carrier-section carrying effect antibiotic was made on the titanium surface and the result was observed.Material and methods:1.Using the electrochemistry anodic oxidation method to make a membrane of TiO₂ nanotube arrays at the titanium surface.2.Using x-ray electromagnetic spectrum(EDS),x-ray diffraction(XRD),scanning electron microscope(SEM)and contact angle(CA)analysator to analyze the surface composition,crystal structure,surface shape and surface invasion of the membrane of TiO₂ nanotube arrays. 3.Using a self-assembly method,at the basis of the membrane of TiO₂ nanotube arrays,to make a super-hydrophobic surface by modifying the surface with a hypo-energy materials.4.Analying the super-hydrophobicity of titanium surface after self-assembly through a CA analysator5.Comparing the effects of different surfaces on bacterial adhesion in vitro,6.Observing the adsorbability of the membrane of TiO₂ nanotube array through the experiment of medicamentous adsorbing and delivering.7.Observing the antibiosis efficacy of the membrane of TiO₂ nanotube array with medicine through vivo and vitro antibiosis experiments.Results:Surface shape:by controlling the parameters of reaction voltage and reaction time,a regular and uniformity tubiform can be made on the Ti-surface and forming a brush of nanotube array in a solution with fluorine.The character of the surface structure:Nanotube arrays include no elements but Ti and oxygen.Its crystal form can be changed with heat-treatment.When the temperature was reached on 450℃,it can be turned from amorphous type into anatase type.After oxidization of the nanotube array on the Ti-surface,its hydrophilicity increases,and the CA decreases from 80.4°±1.5°to 48.6°±1.0°and 20.2°±2.7°.The bacteriostasis result of hyper-hydrophobic surface:When modificationing the TiO₂ nanotube array with hypo-energy surface material PETS, the CA can be 156°±1.0°.As certificated by vitro experiment of bacteriostasis, compare to hydrophilic and common hydrophobic surfaces,the bacteriostasis function of hyper-hydrophobic surface may degrade by 50%-90%which can reduce the bacterial adhesion effectively.Medicine loading and delivering of TiO₂ nanotube:the adsorbability of TiO₂ nanotube is great,and the Vancomycin and Tobramycin can be absorbed into tubes.But to the aspect of antibiotic dilivery,it is less and unregular and needs further exploratory and investigation.The antibiosis experiment of ZiO₂ nanotube with medicine:As verified by vitro experiment,TiO₂ nanotube with medicine cannot decrease bacterial adhesion, but can kill 50%-90%attached bacterial.In animal experiment,TiO₂ nanotube with vancomycin medicine can improve the clinic symptoms of bone Infection and osteomyelitis.As demonstrated on bone scan,compared to the control side, the ROI values on the inferior femur of trial side were much less.And on micro CT,contrast to the trial side,cortical bone destroy and periosteal reaction can be seen on control side obviously.The result of pathology is the same as micro CT, that is that the degree of bone marrow infection,cortical bone destroy and periosteal reaction on the trial side is higher than the control side.Conclusion:1.a membrane of TiO₂ nanotube array was made at the titanium surface with galvanochemistry anodic oxidation methods.2.On the surface of the membrane of TiO₂ nanotube array, super-hydrophobic surface was formed,decreasing the ability of bacterial adhesion and planting obviously.3.The adsorbability of TiO₂ nanotube is great and it can become a new medicine-carrier adsorbing effective antibiotic to treat or prevent the infection causing by implants.