Preparation and long-term antibacterial activity of TiO2 nanotubes loaded with Ag nanoparticles and Ag ions

Abstract

In this work anatase TiO₂ nanotubes were prepared by hydrothermally treating a suspension of anatase TiO₂ particles in alkaline solutions without the following calcination process. Ag nanoparticles and Ag ions were both loaded on TiO₂ nanotubes by immersion in AgNO₃ solutions followed by ultraviolet light radiation. The chemical and morphological features of the products, and the Ag release properties were investigated. The results demonstrated that the “open-ended” anatase TiO₂ nanotubes with diameters of about 10 nm and lengths of over 100 nm were successfully prepared; 15.3 wt% of AgNO₃ was loaded into the hollow tubular nanostructures and 9.2 wt% of Ag nanoparticles adhered uniformly to the walls of the nanotubes. The “open-ended” hollow tubular nanostructure of TiO₂ nanotubes could act as a controller for the Ag release, and this endowed the Ag–TiO₂ nanotubes with an extended antibacterial period. The long-term antibacterial activities of the resultant Ag–TiO₂ nanotubes were examined against both Gram-negative bacteria and Gram-positive bacteria. It was confirmed that the “open-ended” hollow tubular nanostructure of TiO₂ nanotubes and the dual action of Ag nanoparticles and Ag ions allowed the Ag–TiO₂ nanotubes to attain long-term antibacterial activity, which enhanced the antibacterial performance of Ag-based antibacterial agents.