Mechanisms of the pH dependent generation of hydroxyl radicals and oxygen induced by Ag nanoparticles.
Many of the chemical and biological effects of silver nanoparticles (Ag NPs) are attributed to the generation of reactive oxygen species (ROS). ESR spectroscopy was used to provide direct evidence for generating ROS during decomposition of H(2)O(2) assisted by Ag NPs. Hydroxyl radical formation was observed under acidic conditions and was accompanied by dissolution of Ag NPs. In contrast, evolution of O(2) was observed in alkaline solutions containing H(2)O(2) and Ag NPs; however, no net dissolution of Ag NPs was observed due to re-reduction of Ag(+) as evidenced by a cyclic reaction. Since H(2)O(2) is a biologically relevant product being continuously generated in cells, these results obtained under conditions mimicking different biological microenvironments may provide insights for finding new biomedical applications for Ag NPs and for risk assessment.
Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, MD 20740, USA.
Weiwei
W
He
Yu-Ting
YT
Zhou
Wayne G
WG
Wamer
Mary D
MD
Boudreau
Jun-Jie
JJ
Yin
D004578:Electron Spin Resonance Spectroscopy; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D017665:Hydroxyl Radical / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000737:chemistry*; D012834:Silver / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet
C045076:Fenton's reagent; D017665:Hydroxyl Radical; D012834:Silver; D006861:Hydrogen Peroxide; D007501:Iron; D010100:Oxygen