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.