Fabrication of a promising hierarchical porous surface on titanium for promoting biocompatibility

The effects of the nano-titanium hydrides (nano-γ-TiH) phase on the formation of nanoporous Ti oxide layer by the potential approach (hydrogen fluoride (HF) pretreatment and sodium hydroxide (NaOH) anodization) were investigated using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy. The nano-γ-TiH phase was formed by the HF pretreatment with various current densities. After the NaOH anodization, the nano-γ-TiH phase was dissolved and transformed into nanoporous rutile-Ti dioxide (R-TiO₂). As the Ti underwent HF pretreatment and NaOH anodization, the microstructure on the surface layer was transformed from α-Ti→(α-Ti + nano-γ-TiH)→(α-Ti + R-TiO₂). In-vitro biocompatibility also indicated that the Ti with a hierarchical porous (micro and nanoporous) TiO₂ surface possessed great potential to enhance cell adhesion ability. Thus, the potential approach can be utilized to fabricate a promising hierarchical porous surface on the Ti implant for promoting biocompatibility.