Kinetic Analysis of Superoxide Anion Radical-Scavenging and Hydroxyl Radical-Scavenging Activities of Platinum Nanoparticles

• DOI: 10.1021/la704046f
• Publication Date: 2008-06-14T06:01:52Z
• Authors: Takeki Hamasaki; Taichi Kashiwagi; Toshifumi Imada; Noboru Nakamichi; Shinsuke Aramaki; Kazuko Toh; Shinkatsu Morisawa; Hisashi Shimakoshi; Yoshio Hisaeda; Sanetaka Shirahata
• Keywords: Hydroxyl radical; Hypoxanthine; HeLa; Scavenging; Xanthine

There are few reports on the physiological effects of metal nanoparticles (nps), especially with respect to their functions as scavengers for superoxide anion radical (O2(.-)) and hydroxyl (.OH). We tried detect scavenging activity Pt nps using a hypoxanthine-xanthine oxidase system O2(.-) Fenton UV/H2O2 .OH. Electron spin resonance analysis revealed that 2 nm particle size have ability scavenge The calculated rate constant O2(.-)-scavenging reaction was 5.03 +/- 0.03 x 10(7) M (-1) s (-1). However, UV/H 2O in presence suggested .OH-scavenging cannot be determined both systems. Among sizes tested from 1 5 nm, showed highest ability. Almost no cytotoxicity observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, MRC-5) were exposed at concentrations high 50 mg/L. scavenged intrinsically generated reactive oxygen species (ROS) HeLa cells. Additionally, significantly reduced levels intracellular by UVA irradiation subsequently protected ROS damage-induced cell death. These findings suggest may new type antioxidant capable circumventing paradoxical conventional antioxidants.