The role of cerium redox state in the SOD mimetic activity of nanoceria
The role of cerium redox state in the SOD mimetic activity of nanoceria
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DOI：
10.1016/j.biomaterials.2008.03.014
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发表时间：
2008-06-01
期刊：
影响因子：
14
通讯作者：
Self, William T.
中科院分区：
文献类型：
--
作者：
Heckert, Eric G.;Karakoti, Ajay S.;Self, William T.
氧化铈纳米颗粒（nanoceria）最近已被证明可以保护细胞免受细胞培养和动物模型中的氧化应激。使用铁细胞色素C测定，纳米氧化铈已显示出超氧化物歧化酶（SOD）活性，并且这种模拟活性已被假定为负责纳米氧化铈的细胞保护。纳米氧化铈的抗氧化性质的本质，特别是什么物理特性使纳米氧化铈有效清除超氧阴离子，是知之甚少。在这项研究中，电子顺磁共振（EPR）分析证实了纳米氧化铈作为SOD模拟物的反应性。用过氧化氢处理的纳米氧化铈的X射线光电子能谱（XPS）和紫外-可见分析表明，Ce 3（+）/4（+）比率的降低与SOD模拟活性的损失直接相关。这些结果强烈表明，纳米氧化铈的表面氧化态在纳米氧化铈的SOD模拟活性中起着不可或缺的作用，并且纳米氧化铈对超氧化物的抑制能力与颗粒表面的铈（III）浓度直接相关。(c)2008爱思唯尔有限公司保留所有权利。
Cerium oxide nanoparticles (nanoceria) have recently been shown to protect cells against oxidative stress in both cell culture and animal models. Nanoceria has been shown to exhibit superoxide dismutase (SOD) activity using a ferricytochrome C assay, and this mimetic activity that has been postulated to be responsible for cellular protection by nanoceria. The nature of nanoceria's antioxidant properties, specifically what physical characteristics make nanoceria effective at scavenging superoxide anion, is poorly understood. In this study electron paramagnetic resonance (EPR) analysis confirms the reactivity of nanoceria as an SOD mimetic. X-ray photoelectron spectroscopy (XPS) and UV-visible analyses of nanoceria treated with hydrogen peroxide demonstrate that a decrease in the Ce 3(+)/4(+) ratio correlates directly with a loss of SOD mimetic activity. These results strongly suggest that the surface oxidation state of nanoceria plays an integral role in the SOD mimetic activity of nanoceria and that ability of nanoceria to scavenge superoxide is directly related to cerium(III) concentrations at the surface of the particle. (c) 2008 Elsevier Ltd. All rights reserved.