Kinetic Analysis of Superoxide Anion Radical-Scavenging and Hydroxyl Radical-Scavenging Activities of Platinum Nanoparticles
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- 作者：Takeki Hamasaki ; Taichi Kashiwagi ; Toshifumi Imada ; Noboru Nakamichi ; Shinsuke Aramaki ; Kazuko Toh ; Shinkatsu Morisawa ; Hisashi Shimakoshi ; Yoshio Hisaeda ; Sanetaka Shirahata
- 刊名：Langmuir
- 出版年：2008
- 出版时间：July 15, 2008
- 年：2008
- 卷：24
- 期：14
- 页码：7354 - 7364
- 全文大小：1007K
- 年卷期：v.24,no.14(July 15, 2008)
- ISSN：1520-5827
文摘
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 radical (·OH). We tried to detect the scavenging activity of Pt nps using a hypoxanthine−xanthine oxidase system for O2·− and using a Fenton and a UV/H2O2 system for ·OH. Electron spin resonance analysis revealed that 2 nm particle size Pt nps have the ability to scavenge O2·− and ·OH. The calculated rate constant for the O2·−-scavenging reaction was 5.03 
0.03 × 107 M−1 s−1. However, the analysis of the Fenton and UV/H2O2 system in the presence of Pt nps suggested that the ·OH-scavenging reaction cannot be determined in both systems. Among particle sizes tested from 1 to 5 nm, 1 nm Pt nps showed the highest O2·−-scavenging ability. Almost no cytotoxicity was observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, and MRC-5) were exposed to Pt nps at concentrations as high as 50 mg/L. Pt nps scavenged intrinsically generated reactive oxygen species (ROS) in HeLa cells. Additionally, Pt nps significantly reduced the levels of intracellular O2·− generated by UVA irradiation and subsequently protected HeLa cells from ROS damage-induced cell death. These findings suggest that Pt nps may be a new type of antioxidant capable of circumventing the paradoxical effects of conventional antioxidants.
0.03 × 107 M−1 s−1. However, the analysis of the Fenton and UV/H2O2 system in the presence of Pt nps suggested that the ·OH-scavenging reaction cannot be determined in both systems. Among particle sizes tested from 1 to 5 nm, 1 nm Pt nps showed the highest O2·−-scavenging ability. Almost no cytotoxicity was observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, and MRC-5) were exposed to Pt nps at concentrations as high as 50 mg/L. Pt nps scavenged intrinsically generated reactive oxygen species (ROS) in HeLa cells. Additionally, Pt nps significantly reduced the levels of intracellular O2·− generated by UVA irradiation and subsequently protected HeLa cells from ROS damage-induced cell death. These findings suggest that Pt nps may be a new type of antioxidant capable of circumventing the paradoxical effects of conventional antioxidants.