Formation of hydroxyapatite within porous TiO₂ layer by micro-arc oxidation coupled with electrophoretic deposition

Micro-arc oxidation (MAO) is commonly used to modify the surface of Ti-based medical implants with a bioactive and porous titanium oxide (TiO₂) layer. This study reports a novel method of incorporating hydroxyapatite (HA) within the TiO₂ layer by coupling MAO with an electrophoretic deposition (EPD) process. A HA-incorporated, porous TiO₂ layer was produced successfully on the Ti substrate using the EPD-coupled MAO treatment, as confirmed by electron microscopy observations. Addition of ethanol to the electrolyte solution containing the fine HA particles was essential to reduce the level of gaseous emission on the anode, which obstructs the attachment of HA particles. In vitro cellular assays showed that the incorporation of HA significantly improved the osteoblastic activity on the coating layer.