Titanium and its alloys are widely used in body implants. Infection and non-acceptance of implanted parts in the body is one of the most important problems caused by implants. In this research, in order to deal with this problem and create antibacterial properties, the surface of Ti6Al4V was anodized and modified using different methods. First, disc-shaped samples of Ti6Al4V alloy with a diameter of 14 mm were anodized to form surface porosity and holes. For anodizing and forming the oxide layer, amounts of 10.5, 15, 17.5, 20 and 25 ml of sulfuric acid were used in 70 ml of deionized distilled water solution called electrolyte for a period of 6 minutes with a voltage of 70 volts. In this regard, silver nanoparticles with amounts of 0.64, 0.96 and 1.28 grams per 60 ml of deionized water applied by ion exchange method were used in one of the cases. Also, in another case, the pectin coating applied by immersion method was used to modify the anodized Ti6Al4V surface, and finally the pectin coating along with silver (in the mentioned amounts) added to the anodized Ti6Al4V surface by immersion method was eva‎luated. . Using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) images, in order to investigate the formation of oxide layer and cavities caused by the anodizing process, the placement of silver nanoparticles on the surface and inside the pores, the formation of the coating Pectin and pectin along with silver on the surface of the anodized samples, the formation of hydroxyapatite on the surface of the samples was validated to check the bioactivity property. In order to ensure the formation of pectin polymer coating on the anodizing samples, infrared spectroscopy with Fourier transform (ATR) was used and the effect of bonding pectin with silver nanoparticles with amounts of 0.64, 0.96 and 1.28 grams in a solution of 20 ml of water was investigated. Also, the adhesion strength of the anodizing coating was eva‎luated and it was found that by increasing the amount of sulfuric acid more than 17.5 ml, the adhesion strength of the coating decreased. Corrosion resistance of Ti6Al4V and modified surfaces was investigated using Electrochemical Impedance Spectroscopy (EIS) test and it was found that silver added to the surface of the anodizing sample with the amount of 1.28 grams has the highest corrosion resistance compared to Ti6Al4V, anodizing samples, added silver with amounts of 0.64, 0.96 and 1.28 grams, pectin coating and pectin with silver (in the mentioned amounts). Wetting test was used to check the hydrophilicity of samples containing pectin and it was found that the sample with 1.2 grams of pectin in 20 ml of water has the highest wetting rate. In order to eva‎luate the bioactivity behavior, the formation of hydroxyapatite on the surface of the above samples was eva‎luated and it was observed that the highest amount of hydroxyapatite was formed on the anodizing sample with pectin coating along with 1.28 grams of silver. To eva‎luate the antibacterial effect of the modified surfaces the method of haleh test and two types of gram positive and gram negative bacteria were used. The results showed that according to the results of the percentage of porosity and adhesion in the amount of 17.5 ml, this amount has been used as the optimal amount for anodizing and surface modification in the rest of the research. The results of the electrochemical impedance test showed that the 1.28 gram silver sample has the highest resistance compared to other samples. Among the three applied methods, despite the antibacterial properties of pectin, this coating caused a decrease in the silver level and the slow release of silver ions, so that this coating showed poor performance compared to the surface of Ti6Al4V anodized with silver nanoparticles. The best surface modification performance against bacteria is related to Ti6Al4V anodized with 1.28 grams of silver.

عباس بهرامي , عبدالمجيد اسلامي

فرزانه علي حسيني

مسعود عطاپور , مهدي رفيعائي