Surface-Mediated Production of Hydroxyl Radicals as a Mechanism of Iron Oxide Nanoparticle Biotoxicity
Surface-Mediated Production of Hydroxyl Radicals as a Mechanism of Iron Oxide Nanoparticle Biotoxicity
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DOI：
10.1021/ja104683w
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发表时间：
2011-01-12
影响因子：
15
通讯作者：
Smirnov, Alex I.
中科院分区：
文献类型：
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作者：
Voinov, Maxim A.;Pagan, Jason O. Sosa;Smirnov, Alex I.
纳米氧化铁在纳米技术中的新兴应用将大量纳米材料引入人类环境，从而引起了一些关注。在这里，我们报告说，γ-Fe 2 O3纳米粒子的直径20-40 nm的表面介导的生物相关的超氧化物驱动的芬顿反应的条件下，高活性的羟基自由基（OH）的生产。通过进行比较自旋捕获EPR实验，我们表明，自由基的产生主要归因于催化反应在纳米粒子的表面，而不是由溶解的金属离子释放的纳米粒子所造成的，如以前所认为的。此外，在纳米颗粒表面上的催化中心被发现是至少50倍更有效的OH中心点自由基生产比溶解的Fe 3+离子。传统的表面改性方法，如钝化的纳米粒子表面与高达935分子的油酸或高达18分子的牛血清白蛋白/氧化铁核心被发现是相当无效的抑制羟基自由基的产生。本研究中开发的实验方案可用作开发分析测定的方法之一，用于评估各种纳米材料的自由基生成活性，这些活性可能与其生物毒性有关。
Emerging applications of nanosized iron oxides in nanotechnology introduce vast quantities of nanomaterials into the human environment, thus raising some concerns. Here we report that the surface of gamma-Fe2O3 nanoparticles 20-40 nm in diameter mediates production of highly reactive hydroxyl radicals (OH) under conditions of the biologically relevant superoxide-driven Fenton reaction. By conducting comparative spin-trapping EPR experiments, we show that the free radical production is attributed primarily to the catalytic reactions at the nanoparticles' surface rather than being caused by the dissolved metal ions released by the nanoparticles as previously thought. Moreover, the catalytic centers on the nanoparticle surface were found to be at least 50-fold more effective in OH center dot radical production than the dissolved Fe3+ ions. Conventional surface modification methods such as passivating the nanoparticles surface with up to 935 molecules of oleate or up to 18 molecules of bovine serum albumin per iron oxide core were found to be rather ineffective in suppressing production of the hydroxyl radicals. The experimental protocols developed in this study could be used as one of the approaches for developing analytical assays for assessing the free radical generating activity of a variety of nanomaterials that is potentially related to their biotoxicity.