| Titanium has been widely used in oral implants due to its good biocompatibility and elastic modulus matching with natural bone tissue.However,as an inert metal,it lacks antibacterial activity and is difficult to prevent postoperative infection and peri-implantitis.Therefore,the surface modification of titanium implants to obtain good antibacterial properties has become one of the research hotspots at home and abroad.In recent years,the construction of titanium implant surface containing nanostructure and the preparation of antimicrobial coating to improve its antimicrobial performance have attracted extensive attention.Titanium dioxide nanotubes constructed in situ on titanium surface are regarded as excellent carriers for antimicrobial drugs because of their large specific surface area,stable binding with titanium substrate and slow release function.Inorganic antimicrobial agents,represented by silver,have become a hot spot in the field of antimicrobial materials because of their excellent antibacterial properties and low resistance to drug resistance.In this study,the uniform nanotube structure was prepared on the surface of pure titanium by anodic oxidation method,and the silver-containing mixed solution was prepared by hydrothermal method using chitosan as reducing agent and stabilizer.The silver-loaded titanium nanotube surface coating was successfully constructed on the surface of pure titanium by layer self-assembly technology.The results showed that the coating had good antibacterial properties,which provided a new method for the anti-bacterial modification of titanium implant surface and the prevention and treatment of peri-implantitis.Specific experimental contents are as follows:The first part: the treatment of titanium sheet and the preparation of TiO2 nanotubesTitanium plate processing into 15 mm in diameter,0.25 mm thick circular titanium plate,after grinding,ultrasonic cleaning,constant temperature drying process step by step,into the ammonium fluoride electrolyte solution,under 20 v dc stabilized voltage anodic oxidation method and treatment of 3 h,the titanium surface preparation of the titanium dioxide nanotubes array structure,and by using FESEM observation of sample surface morphology characteristics.Compared with the mirror-like surface of smooth titanium sheet,the TiO2 nanotube array on the surface of the sample prepared in this experiment showed a uniformly distributed honeycomb structure,with a cavity diameter of about 70 nm and a height of about 700 nm.The second part:preparation of silver-loaded coating on titanium dioxide nanotubesUsing chitosan reduction of silver ions,the chitosan mixed solution containing silver is prepared,and compared with heparin sodium solution form polyelectrolyte solution system,using layers of self-assembly technology in titanium dioxide nanotubes coating on the silver surface was prepared by field emission scanning electron microscopy(sem)and contact Angle meter,X-ray photoelectron spectrometer,inductively coupled plasma emission spectrometer analysis of samples,testing the titanium dioxide nanotubes preparation of silver coating effect.The field emission scanning electron microscopy(SEM)results showed that the surface of TiO2 nanotubes disappeared after loading polyelectrolyte multilayer film,and the surface was relatively smooth,and the porphyular structure was visible due to the uneven distribution of the film layer.The contact Angle test showed that the number of contact angles on the surface of TiO2 nanotubes was significantly reduced compared with that of pure TiO2,and the hydrophilicity was enhanced.The surface hydrophilicity of TiO2 nanotubes was decreased after loading silver coating,but it was still improved compared with that of pure TiO2.XPS test showed that the strength of Ti peak weakened and Ag peak appeared after coating loading,which proved that the silver-loaded polyelectrolyte multilayer film was successfully loaded on the surface of the sample.The ICP-AES test results showed that the silver release rate of the silver-loaded coating samples was faster in the first 24 h,then slowed down gradually,and continued to release until the sixth day.The third part: Antimicrobial effect of silver-loaded TiO2 nanotubes on Porphyromonas gingivalisPorphyromonas gingivalis was added to a 12-well plate containing silver-titanium dioxide nanotube material for anaerobic culture for 48 h,and a proper amount of the bacterial liquid was absorbed and diluted,and then cultured and counted.In addition,the 12-well plate was discarded from the medium and stained with crystal violet.The absorbance value was measured with a microplate analyzer and the amount of biofilm formation was calculated to evaluate the antibacterial effect of the sample.Mouse 3T3 cells were cultured on the surface of silver-loaded TiO2 nanotubes for 1 day and 3 days respectively for fluorescence staining experiments.Cell number and growth morphology were observed to evaluate the cytotoxicity of the samples.The silver-loaded TiO2 nanotubes antibacterial coating had good antibacterial properties,and the samples showed weak cytotoxicity in the early stage.With the passing of time,the toxicity decreased gradually,and had no obvious effect on the growth of cells.In this study,the uniform nanotube structure was prepared on the surface of pure titanium by anodic oxidation method,and the mixed solution of AgNP was prepared by hydrothermal method using chitosan as reducing agent and stabilizer.The surface coating of silver-loaded titanium nanotubes was successfully constructed on the surface of pure titanium by layer upon layer self-assembly technology.The results showed that the coating had good antibacterial properties,which provided a new method for the anti-bacterial modification of titanium implant surface and the prevention and treatment of peri-implantitis. |
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