Department of Civil & Environmental Engineering, University of California, Los Angeles, California 90095, USA.
Environ Sci Technol. 2011 Oct 15;45(20):8989-95. doi: 10.1021/es201675m. Epub 2011 Sep 16.
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.
采用高通量筛选方法，评估了包含 TiO₂ 晶相、Ag 含量和合成方法变化的 Ag-TiO₂ 杂化纳米粒子的杀菌活性。Ag-TiO₂ 杂化纳米粒子通过湿浸渍或 UV 光沉积到 Degussa P25 和 DuPont R902 TiO₂ 纳米粒子上制备而成。通过 ICP、TEM 和 XRD 分析证实了 Ag 的存在。在锐钛矿/金红石 P25 TiO₂ 纳米粒子上形成的 Ag 纳米粒子的尺寸小于在纯金红石 R902 上形成的 Ag 纳米粒子。当用 UV 光激活时，所有 Ag-TiO₂ 杂化纳米粒子都表现出比单独 UV 光、Ag/UV 或 UV/TiO₂ 更强的杀菌活性。在黑暗条件下进行的实验中，Ag-TiO₂ 纳米粒子的杀菌活性大于裸露的 TiO₂（惰性）或纯 Ag 纳米粒子，这表明杂化材料产生了与光活性无关的协同抗菌作用。此外，从 Ag-TiO₂ 纳米粒子中溶解的 Ag(+) 少于从 Ag 纳米粒子中溶解的 Ag(+)，这表明 Ag-TiO₂ 的抗菌活性不仅是由释放有毒金属离子引起的。显然，纳米技术可以产生更有效的杀菌剂；然而，挑战仍然在于确定利用这些令人兴奋的新材料特性的实际方法。
