In Vitro Corrosion Behavior and Cytotoxicity of Polycaprolactone–Akermanite-Coated Friction-Welded Commercially Pure Ti/AZ31 for Orthopedic Applications

This study deals with the corrosion and bioactivity behavior of biodegradable friction-welded CP-Ti/AZ31 joints. The investigations were carried out on the bare, PCL-coated and PCL–akermanite (AKT)-coated joints immersed in simulated body fluid. The samples were subjected to polarization and impedance corrosion tests, weight loss and pH monitoring and cytotoxicity investigations as well as cell adhesion test. The results of corrosion tests and weight loss measurements indicated that whereas the bare alloy shows the highest corrosion rate through 7 days (15.945 mm/y), the PCL–AKT-coated sample presented significantly improved results, even when the soaking period was prolonged to 30 days. The PCL–AKT-coated sample also showed the best biocompatibility, as the cell viability was measured to be 97.52%. The Ca/P ratio was also measured to be about 1.64 for PCL–AKT-coated sample, indicating favorable osteogenic behavior. The results of alizarin red cell staining and absorption spectrum as well as alkaline phosphatase activity confirmed superior osteogenic behavior of the PCL–AKT-coated sample. It was found that the CP-Ti/AZ31 samples coated with PCL–AKT obtained suitable corrosion resistance and cellular response, thus presenting a good potential to be used in orthopedic applications.