Fabrication of biofunctional oxide layer with potential self-antibacterial performance for biomedical applications

In the present study, field-emission scanning electron microscopy, Auger electron spectroscopy, surface roughness instrument, and transmission electron microscopy were performed to investigate a potential self-antibacterial oxide layer on the titanium (Ti) surface formed by the anodization with hydrogen fluoride (HF) acid pretreatment through cathodization. The in vitro antibacterial properties were determined using the Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli) according to JIS Z2801: 2010 specification. Analytical results showed that the topography with a flat nano-porous structure was formed on the anodized Ti specimen with 0.5% HF pretreatment. The pretreatment with a concentration of 0.5% HF caused a thicker Ti dioxide layer (∼350 nm) formation on the Ti surface after anodization. Moreover, the antibacterial rate also proved that the anodized Ti specimen with 0.5% HF pretreatment had the potential to inhibit both S. aureus (75.1 ± 3.5%) and E. coli (90.5 ± 1.6%) growth (*p < 0.05). Hence, the anodization with HF pretreatment through cathodization approach can be used to fabricate a biofunctional surface with self-antibacterial performance that is required for biomedical Ti implant applications.