title: Platinum nanoparticle is a useful scavenger of superoxide anion and hydrogen peroxide.
abstract: Bimetallic nanoparticles consisting of gold and platinum were prepared by a citrate reduction method and complementarily stabilized with pectin (CP-Au/Pt). The percent mole ratio of platinum was varied from 0 to 100%. The CP-Au/Pt were alloy-structured. They were well dispersed in water. The average diameter of platinum nanoparticles (CP-Pt) was 4.7 +/- 1.5 nm. Hydrogen peroxide (H(2)O(2)) was quenched by CP-Au/Pt consisting of more than 50% platinum whereas superoxide anion radical (O(2)(-)) was quenched by any CP-Au/Pt. The CP-Au/Pt quenched these two reactive oxygen species in dose-dependent manners. The CP-Pt is the strongest quencher. The CP-Pt decomposed H(2)O(2) and consequently generated O(2) like catalase. The CP-Pt actually quenched O(2)(-) which was verified by a superoxide dismutase (SOD) assay kit. This quenching activity against O(2)(-) persisted like SOD. Taken together, CP-Pt may be a SOD/catalase mimetic which is useful for medical treatment of oxidative stress diseases.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Kajita
authors.forename: Keisuke
authors.initials: K
authors.lastname: Hikosaka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Iitsuka
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanayama
authors.forename: Naoki
authors.initials: N
authors.lastname: Toshima
authors.forename: Yusei
authors.initials: Y
authors.lastname: Miyamoto
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry* / Q000378:metabolism; D053758:Nanoparticles; D036103:Nanotechnology; D016877:Oxidants / Q000737:chemistry* / Q000378:metabolism; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010984:Platinum / Q000737:chemistry* / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000737:chemistry* / Q000378:metabolism; D014527:Uric Acid / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D016877:Oxidants; D017382:Reactive Oxygen Species; D013481:Superoxides; D014527:Uric Acid; D010984:Platinum; D006046:Gold; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen