Characterization and preosteoblastic behavior of hydroxyapatite‐deposited nanotube surface of titanium prepared by anodization coupled with alternative immersion method

Abstract

The modification on the titanium (Ti) implant surface is an effective method to improve the bioactivity of Ti. In this study, a hydroxyapatite (HA)-deposited nanotubular Ti surface was prepared by anodization coupled with an alternative immersion method (AIM). Surface physicochemical characteristics including morphology, microstructure, composition, roughness were evaluated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Preosteoblast cell (MC3T3-E1) behavior on the HA-deposited nanotube surface, including cell morphology, proliferation, alkaline phosphatase (ALP) activity, osteocalcin secretion, and mineralization, were also investigated. The untreated nanotube surface and bare Ti were used as controls. The results showed that synthetic HA crystals could be efficiently grown on/inside the nanotubes after AIM treatment in saturated Ca(OH)(2) and 0.02M (NH(4))(2) HPO(4). The amount of synthetic HA on nanotube layer was dependent on the number of dipping cycles. Significant increases in ALP activity and osteocalcin production on day 7 and 14 and calcium deposition on day 21 (P < 0.05) were observed for HA-deposited nanotubular Ti surface when compared with untreated nanotube layer and bare Ti. However, the cell proliferation rate on HA-deposited nanotube surfaces was slowed down significantly (P < 0.05). All these results indicated that this HA-deposited nanotube surface might have the potential benefit to enhance implant osseointegration. The synthetic HA TiO(2) nanotube loading might be a highly promising path to improve the bioactivity of Ti-based implants.