Enhanced initial cell responses to chemically modified anodized titanium

Background: Previously, we reported that anodized porous titanium implants have photocatalytic hydrophilicity. However, this effect was not always sufficient for the significant improvement of bone apposition. Purpose: The purpose of this study was to improve the photocatalytic properties of porous titanium implants by the fluoride modification of the anodized titanium dioxide (TiO2), and to investigate the initial cell response to it. Materials and Methods: The ideal concentration of ammonium hydrogen fluoride (NH4F-HF2) used in this study was determined by a static water contact angle assay. The ideal concentration of NH4F-HF2 was 0.175%, and experimental disks were treated with this concentration. A pluripotent mesenchymal cell line, C2C12, was cultured on the disks in order to investigate cell attachment, morphology, and proliferation. Results: Cell attachment after 30 minutes of culturing was significantly higher for the ultraviolet-irradiated, fluoride-modified anodized TiO2 (p < .05), and the simultaneous scanning electron microscope observation showed a rather flattened and extended cell morphology. The proliferation rate after 24 hours was also significantly higher for the fluoride-modified anodized TiO2. Conclusion: Fluoride chemical modification enhances the hydrophilic property of the anodized TiO2 and improves the initial cell response to it.