Effects of Copper Doping on Fluorohydroxyapatite Coating: Analysis of Microstructure, Biocompatibility, Corrosion Resistance, and Cell Adhesion Characteristics

In this research, Cu-doped fluorohydroxyapatite (Cu-FHAp) coatings containing varying levels of Cu in electrolyte as a dopant were synthesized by the ultrasonic-assisted pulse-reverse electrodeposition method on AZ31 alloy to improve the biocompatibility and corrosion resistance of the alloy for biomedical applications. Microstructural analysis revealed that the inclusion of the Cu dopant results in the formation of a more uniform coating. Energy dispersive spectroscopy analysis highlights a notable incorporation of copper within the fluorohydroxyapatite structure. The increase in Cu content significantly affected surface roughness and elevated hydrophobicity, leading to a contact angle of up to 136°. Electrochemical impedance spectroscopy analysis revealed that all samples containing copper exhibited favorable corrosion resistance, with the sample prepared using the electrolyte containing 0.036 g/L Cu(NO₃)₂ demonstrating the highest corrosion resistance. Cell adhesion evaluation yielded a satisfactory cell adhesion to the coated samples, indicating that the presence of the optimum value of Cu does not induce considerable cytotoxic effects.