In vitro free radical scavenging activity of platinum nanoparticles

Aki Watanabe, Masashi Kajita, Juewon Kim, Atsuhiro Kanayama, Kyoko Takahashi, Tadahiko Mashino, Yusei Miyamoto

Research output: Contribution to journalArticlepeer-review

155 Citations (Scopus)


A polyacrylic acid (PAA)-protected platinum nanoparticle species (PAA-Pt) was prepared by alcohol reduction of hexachloroplatinate. The PAA-Pt nanoparticles were well dispersed and homogeneous in size with an average diameter of 2.0 0.4nm (n = 200). We used electron spin resonance to quantify the residual peroxyl radical () generated from 2,2-azobis (2-aminopropane) dihydrochloride (AAPH) by thermal decomposition in the presence of O2 and a spectrophotometric method to quantify the residual 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical. PAA-Pt scavenged these two radicals in a dose-dependent manner. Platinum was the functional component. PAA-Pt reduced the rate of oxygen consumption required for linoleic acid peroxidation initiated by generated from AAPH, indicating inhibition of the propagation of linolate peroxidation. A thiobarbituric acid test also revealed dose-dependent inhibition of the linolate peroxidation by PAA-Pt. Fifty micromolar platinum, as PAA-Pt, completely quenched 250 νM DPPH radical for 5min. Even when twice diluted in half, the PAA-Pt still quenched 100% of the 250νM DPPH radical. The scavenging activity of PAA-Pt is durable. These observations suggest that PAA-Pt is an efficient scavenger of free radicals.

Original languageEnglish
Article number455105
Issue number45
Publication statusPublished - 2009
Externally publishedYes

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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