Hydroxyaptite nanorods patterned ZrO₂ bilayer coating on zirconium for the application of percutaneous implants

Percutaneous implant requires a tight bond between the underlying dermis of skin and implant surface to prevent epithelial down-growth and infection, while fibroblasts play a key role in the skin-implant integration. In this work, nanorod-shaped hydroxyaptite (HA) with a mean diameter of 70nm and length of 400nm was hydrothermally grown on micro-arc oxidized (MAOed) Ca- and P-doped ZrO₂ to form a bilayer coating. The hydrothermal formation mechanism of HA nanorods was explored, and the adsorption of total protein on the coating from α-MEM medium containing 10% fetal bovine serum was examined. Employing L-929 cells, the behaviors of fibroblasts on the bilayer coating, including adhesion and proliferation were evaluated together the polished Zr and as-MAOed ZrO₂. The obtained results show that the HA nanorods nucleated on ZrO₂ and grew at the expense of the doped Ca and P ions during the hydrothermal treatment (HT). The HA nanorods patterned coating enhanced protein absorption, and significantly improved the adhesion and proliferation of fibroblasts compared to the as-MAOed ZrO₂ and polished Zr. It suggests that the HA nanorods/ZrO₂ coated zirconium has a potential application for percutaneous implants to enhance the attachment of skin.