Surface functionalization of additively manufactured Ti6Al4V scaffolds with CaP/ZnO coatings

A biologically active coating with strong adhesion can improve the inherent bioinert nature of the additively manufactured Ti6Al4V scaffolds. In this research, a calcium phosphate coating containing antibacterial zinc oxide nanoparticles was applied onto the lattice-structured Ti6Al4V scaffolds using the plasma electrolytic oxidation (PEO) method, and its corrosion resistance and in vitro bioactivity were analyzed. The results revealed that the thickness of the CSh (Coat-Short: Scaffold with an approximate porosity size of 2.23 mm and coated) sample coating was approximately 1.8 times thicker that of the coating created on the CL (Coat-Long: Scaffold with an approximate porosity size of 3.74 mm and coated) sample. Zinc oxide nanoparticles in the coating were found to be uniformly dispersed, resulting in a 5.5% reduction in the hydrophilic behavior of the coatings. Moreover, both types of samples, with the reinforcement of the barrier layer, successfully improved the long-term corrosion behavior of the substrate, with a more pronounced effect on the CSh samples. After 14 days of immersion in simulated body fluid, cauliflower-shaped hydroxyapatite deposits were observed across the entire surface of the coatings. MG63 cells on the CSh sample demonstrated a wider spread and greater adhesion compared to other samples. Additionally, the cell viability increased from 83.3 ± 4.1 (% control) in the uncoated sample to 94.9 ± 1.1 (% control). These results suggest that coatings fabricated on scaffold surfaces with smaller porosity (CSh) exhibit more favorable corrosion and biological behavior, highlighting their potential applications in orthopedics.