Surface Characterization and Biocompatibility of Hydroxyapatite Coating on Anodized TiO2 Nanotubes via PVD Magnetron Sputtering.

Hydroxyapatite (HA) coating has received significant attention in the scientific community for the development of implants, and HA coating on titanium oxide (TiO2) nanotubes has shown potential benefits in the improvement of cell proliferation, adhesion, and differentiation. In this study, a HA coating on a TiO2 nanotubular surface was developed to improve the biocompatibility of the titanium (Ti) surface via magnetron sputtering. Scanning electron microscopy (SEM), surface profilometry, and water contact goniometry revealed that HA-coated TiO2 nanotubes influenced the surface roughness (Ra) and hydrophilicity. The XRD and FTIR peaks indicated the presence of crystalline phases of TiO2 (anatase) and HA-coated TiO2 nanotubes after annealing at 500 °C for 120 min. The HA-coated TiO2 nanotubes showed significantly increased Ra and decreased water contact angle (θ) compared to the as-anodized TiO2 nanotubular and bare CP-Ti surfaces. MTS assay using osteoblast-like cells confirmed that the HA-coated TiO2 nanotubular surface provided an enhanced cell attachment and growth when compared to as-anodized TiO2 nanotubular and pure CP-Ti surfaces.