title: Synergistic bactericidal activity of Ag-TiO₂ nanoparticles in both light and dark conditions.
abstract: High-throughput screening was employed to evaluate bactericidal activities of hybrid Ag-TiO₂ nanoparticles comprising variations in TiO₂ crystalline phase, Ag content, and synthesis method. Hybrid Ag-TiO₂ nanoparticles were prepared by either wet-impregnation or UV photo deposition onto both Degussa P25 and DuPont R902 TiO₂ nanoparticles. The presence of Ag was confirmed by ICP, TEM, and XRD analysis. The size of Ag nanoparticles formed on anatase/rutile P25 TiO₂ nanoparticles was smaller than those formed on pure rutile R902. When activated by UV light, all hybrid Ag-TiO₂ nanoparticles exhibited stronger bactericidal activity than UV alone, Ag/UV, or UV/TiO₂. For experiments conducted in the dark, bactericidal activity of Ag-TiO₂ nanoparticles was greater than either bare TiO₂ (inert) or pure Ag nanoparticles, suggesting that the hybrid materials produced a synergistic antibacterial effect unrelated to photoactivity. Moreover, less Ag(+) dissolved from Ag-TiO₂ nanoparticles than from Ag nanoparticles, indicating the antibacterial activities of Ag-TiO₂ was not only caused by releasing of toxic metal ions. It is clear that nanotechnology can produce more effective bactericides; however, the challenge remains to identify practical ways to take advantage of these exciting new material properties.
authors.affiliation: Department of Civil & Environmental Engineering, University of California, Los Angeles, California 90095, USA.
authors.forename: Minghua
authors.initials: M
authors.lastname: Li
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Noriega-Trevino
authors.forename: Nereyda
authors.initials: N
authors.lastname: Nino-Martinez
authors.forename: Catalina
authors.initials: C
authors.lastname: Marambio-Jones
authors.forename: Jinwen
authors.initials: J
authors.lastname: Wang
authors.forename: Robert
authors.initials: R
authors.lastname: Damoiseaux
authors.forename: Facundo
authors.initials: F
authors.lastname: Ruiz
authors.forename: Eric M V
authors.initials: EM
authors.lastname: Hoek
mesh_terms: D003624:Darkness; D008027:Light; D053758:Nanoparticles / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D012834:Silver; D014025:Titanium