Capping antibacterial Ag nanorods aligned on Ti interlayer by mesoporous TiO2 layer

In this work, aligned and compact Ag nanorods capped by sol-gel mesoporous TiO2 layer were grown on Ti/Si(100) in order to be applied in antibacterial applications. The Ag nanorods with a high effective surface were grown by applying an electric field perpendicular to the surface of the Ag/Ti/Si thin film while it was being heat-treated at 700 degrees C in an At + H-2 ambient. The grown silver nanorods had widths and lengths of 20-50 and 250-500 nm with an abundance in {100} facet, respectively. The TiO2 cap layer also had the specific surface area, the total pore volume and the pore diameter of 474 m(2)/g. 0.49 cm(3)/g and 8.0 nm. respectively. Antibacterial activities of the TiO2-capped Ag nanorods against E coli bacteria were examined in the dark and under UV irradiation, and then compared to the corresponding activities of the TiO2-capped Ag thin film and the TiO2-capped Ag nanoparticles grown on the Ti layer. The Ag+ ion release measurements showed that the mesoporous and aqueous TiO2 cap layer can control the silver release process by inter-diffusion of water and silvers thorough its capillary structures, completely different from the ion release behavior of the silver nanorods not capped by the TiO2 layer. The results showed a strong and lasting antibacterial activity for the TiO2-capped Ag nanorods with 2.34 h(-1) for the relative rate of reduction of the number of viable bacteria. (C) 2009 Elsevier B.V. All rights reserved.