Effect of Anodic Oxidation Pulse Voltage on Antibacterial Properties and Biocompatibility of Ti-Ag Alloy

Abstract

For the application of titanium and titanium alloys in orthopedic implant materials, the antibacterial properties and cell biocompatibility determine whether the implant surgery is successful. In this study, a functional anodic oxidation (AO) coating was successfully prepared to modify the surface of Ti-Ag alloy. The surface characteristics of the anodized Ti-Ag alloy were analyzed using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The corrosion characteristics of Ti-Ag samples were tested by an electrochemical workstation. In addition, the antibacterial properties and cell activity were studied by the plate count method and MC3T3-E1 cell staining. The results indicate that the AO process can generate a multi-functional TiO2/Ag2O coating with a large number of block and flower-like structures on the surface of a Ti-Ag alloy. When the AO voltage of the sample is 120 V, the maximum roughness is 0.73 μm and the minimum wetting degree is 23°, which improves the biocompatibility. The corrosion test results show that AO treatment can improve the corrosion resistance of a Ti-Ag alloy. The oxidation voltage is 20 V and the coating has the best corrosion resistance. The corrosion open circuit potential (Eocp) is 107.621 mV and the corrosion current density (icorr) is 2.241 × 10−8 A·cm−2. This coating can promote ion release and show more than 99% of a strong antibacterial ability against S. aureus. The results of the compatibility evaluation by cultured cells showed that the multifunctional coating formed by the anodic oxidation process did not cause cytotoxicity and promoted the adhesion of MC3T3-E1 cells.