Vancomycin-functionalised Ag@TiO2 phototoxicity for bacteria

This study reports on the synthesis of vancomycin (Van)-functionalised Ag@TiO2 nanoparticles and their enhanced bactericidal activities. Van-Ag@TiO2 nanoparticles were prepared by nanoparticle deposition and chemical cross-linking reactions. The catalysts showed high efficiency for the degradation of methylene blue under ultraviolet (UV) illumination. The photocatalytic inactivation of the sulphate-reducing bacteria, Desulfotomaculum, was also studied under UV light irradiation and in the dark using aqueous mixtures of Ag, Ag@SiO2, Ag@TiO2, and Van-Ag@TiO2. The Van-Ag@TiO2 nanoparticles showed a capacity to target Van-sensitive bacteria. They also effectively prevented bacterial cell growth through the functionalised nanoparticles under UV irradiation for 1 h. To investigate the specificity of the catalyst phototoxicity, a Van-resistant bacteria, Vibrio anguillarum, was used as the negative control. The results indicated that Van-Ag@TiO2 nanoparticles had a higher selective phototoxicity for Van-sensitive bacteria. Therefore, the antibiotic molecule-functionalised core-shell nanoparticles allow for selective photokilling of pathogenic bacteria. (C) 2010 Elsevier B.V. All rights reserved.