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

Sci Rep. 2025 Sep 26;15(1):32974. doi: 10.1038/s41598-025-16330-9.

Abstract

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).

Keywords: Anodic oxidation (AO); Antimicrobial activity; Implant applications; Ti45Nb alloy; TiO2 layer; Wettability.

MeSH terms

  • Alloys* / chemistry
  • Alloys* / pharmacology
  • Anti-Bacterial Agents* / chemistry
  • Anti-Bacterial Agents* / pharmacology
  • Anti-Infective Agents* / chemistry
  • Anti-Infective Agents* / pharmacology
  • Electrodes
  • Escherichia coli / drug effects
  • Oxidation-Reduction
  • Staphylococcus aureus / drug effects
  • Surface Properties
  • Titanium* / chemistry
  • Titanium* / pharmacology
  • Wettability

Substances

  • Titanium
  • titanium dioxide
  • Alloys
  • Anti-Bacterial Agents
  • Anti-Infective Agents