Surface characterization, wettability and antimicrobial ability of anodic oxide TiO₂ layers on Ti45Nb alloy

Bacterial infections are among the foremost causes of morbidity and mortality on a global scale. In this study, TiO₂ layers were performed on Ti45Nb alloys by anodic oxidation (AO) process with low voltages. Thus, the aim of this research is to investigate the surface properties, wettability and antimicrobial properties of TiO₂ layers fabricated at low AO voltages on Ti45Nb alloy. The phase structures, morphologies and elemental amounts and distribution of the surfaces were characterized by XRD, Micro-Raman, SEM and EDX. The existence of anatase-TiO₂ was verified on AO layer on Ti45Nb alloy. The wettability of AO layers improved with increasing AO voltage and the surfaces became more and more hydrophilic with increasing voltage. For Escherichia coli as Gram-negative and Staphylococcus aureus as Gram-positive, the counting of both bacteria on TiO₂ layers was less than ones on uncoated Ti45Nb. Moreover, the number of bacteria on the surface increased in direct proportion to the wettability result and increasing AO voltage. The AO layers produced at 25 V indicated maximum inhibition ratio. They inhibited both bacteria at the ratio of 93.3% (E. coli) and 96.7% (S. aureus).