Unveiling the pH influence: Enhancing hydroxyapatite-coated titanium biomedical implants through electrochemical deposition

This study explores the electrochemical deposition (ECD) of hydroxyapatite (HA) coatings onto commercially pure titanium (CP–Ti) substrates, with a focus on biomedical implant applications. The ECD process serves as a useful approach for controlling the growth and characteristics of these HA coatings. Additionally, to refine the crystalline structure and bolster biocompatibility, annealing techniques were employed. The results unveiled distinctive morphologies for HA coatings under varying pH levels of the electrolyte: granular at pH 4, flake-like at pH 6, and needle-like at pH 9, emphasizing the significant impact of electrolyte pH on coating structure. Surface roughness exhibited its peak at pH 4, indicative of the most uneven HA layer formation. In particular, all HA-coated samples displayed heightened hydrophilicity compared to their uncoated CP-Ti counterparts, with pH 6 showing the most substantial decrease in contact angle, suggesting pronounced biocompatibility enhancements. X-ray Diffraction affirmed HA as the predominant phase in the annealed coatings. Electrochemical assessments were conducted to gauge the electrochemical behavior of HA-coated samples. The findings revealed that pH 6 offered the most robust electrochemical behavior, rendering it a promising electrolyte pH condition for HA-coated CP-Ti biomedical implants. This comprehensive investigation highlights the profound influence of the pH of the electrolyte on HA morphology and surface properties, which in turn impact electrochemical behavior in HA-coated CP-Ti for biomedical implant applications. As such, the application of ECD techniques across varying pH levels of the electrolyte emerges as an effective strategy for tailoring HA coatings, thus enhancing their suitability for biomedical implants.