Enhancing antibacterial properties of titanium implants through a novel Ag-TiO₂-OTS nanocomposite coating: a comprehensive study on resist-killing-disintegrate approach

Abstract

Titanium (Ti) implants are widely used in orthopedic and dental applications due to their excellent biocompatibility and mechanical properties. However, bacterial adhesion and subsequent biofilm formation on implant surfaces pose a significant risk of postoperative infections and complications. Conventional surface modifications often lack long-lasting antibacterial efficacy, necessitating the development of novel coatings with enhanced antimicrobial properties. This study aims to develop a novel Ag-TiO₂-OTS (Silver-Titanium dioxide-Octadecyltrichlorosilane, ATO) nanocomposite coating, through a chemical plating method. By employing a ‘resist-killing-disintegrate’ approach, the coating is designed to inhibit bacterial adhesion effectively, and facilitate pollutant removal with lasting effects. Characterization of the coatings was performed using spectroscopy, electron microscopy, and contact angle analysis. Antibacterial efficacy, quantitatively evaluated against E. coli and S. aureus over 168 h, showed a significant reduction in bacterial adhesion by 76.6% and 66.5% respectively, and bacterial removal rates were up to 83.8% and 73.3% in comparison to uncoated Ti-base material. Additionally, antibacterial assays indicated that the ratio of the Lifshitz-van der Waals apolar component to electron donor surface energy components significantly influences bacterial adhesion and removal, underscoring a tunable parameter for optimizing antibacterial surfaces. Biocompatibility assessments with the L929 cell line revealed that the ATO coatings exhibited excellent biocompatibility, with minimal cytotoxicity and no significant impact on cell proliferation or apoptosis. The ATO coatings provided a multi-functionality surface that not only resists bacterial colonization but also possesses self-cleaning capabilities, thereby marking a substantial advancement in the development of antibacterial coatings for medical implants.

Keywords:

• Ag-TiO₂ coating
• octadecyltrichlorosilane (OTS)
• anti-infection
• bacterial adhesion
• biocompatibility

Acknowledgements

The authors gratefully acknowledge the financial support from the Natural Science Foundation of Chongqing, China [grant number: cstc2021jcyj-msxm], Special Support for Postdoctoral Research of Chongqing, China (2020) Natural Science Foundation of China (51701131) and Natural Science Foundation of Fujian Province Project, China (2020J05212). We are also grateful for the support from the Core Facility Center (CFC) at Capital Medical University, Beijing Area Major Laboratory of Peptide and Small Molecular Drugs.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Natural Science Foundation Project of Chongqing, Chongqing Science and Technology Commission [cstc2021jcyj-msxm]; Natural Science Foundation of China and Special Support for Postdoctoral Research of Chongqing [51701131]; Natural Science Foundation of Fujian Province Project [2020J05212].