Oxidase-like activity of polymer-coated cerium oxide nanoparticles.
Oxidase-like activity of polymer-coated cerium oxide nanoparticles.
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DOI：
10.1002/anie.200805279
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发表时间：
2009
影响因子：
16.6
通讯作者：
Perez, J. Manuel
中科院分区：
文献类型：
--
作者：
Asati, Atul;Santra, Santimukul;Kaittanis, Charalambos;Nath, Sudip;Perez, J. Manuel
近年来，已经报道了纳米材料独特的催化活性。[1]这些尺寸依赖性的性质，这往往是不存在的散装材料，是在能量储存，化学合成和生物医学应用中的多种应用的新型催化剂的设计的基础。[2，3]氧化铈已被广泛用于汽车排气系统的催化转化器，作为紫外线吸收剂，并作为燃料电池的电解质。[4-7]最近，人们发现氧化铈纳米颗粒（nanoceria）在生理pH值下具有抗氧化活性，并且已经报道了这些材料在生物医学应用中的潜在用途，例如防止辐射损伤，氧化应激和炎症。[8-12]这些纳米颗粒作为抗氧化剂的能力取决于它们从Ce 3+可逆地转换为Ce 4+的能力。[11]此外，生物相容性葡聚糖涂层纳米氧化铈（DNC）的合成及其在水溶液中的稳定性增强最近已被报道。[12]在本文中，我们报道了纳米氧化铈在酸性pH值下具有固有的氧化酶样活性，因为它可以在没有任何氧化剂（例如过氧化氢）的情况下快速氧化一系列有机底物。所观察到的活性不仅是pH依赖性的，而且还取决于氧化铈纳米颗粒的尺寸以及聚合物涂层的厚度。在这些发现的基础上，我们设计了一种免疫测定法，其中叶酸缀合的氧化铈纳米颗粒通过与表达叶酸的癌细胞结合并通过敏感的比色底物（染料）的催化氧化促进检测来提供双重功能。氧化铈纳米颗粒在水介质中独特的pH依赖性氧化酶样活性使其成为生物技术和环境化学中广泛潜在应用的有力工具。对于我们的第一组实验，我们研究了DNC制剂[12]是否可以在低pH值下促进一系列有机染料的氧化。在这些实验中，我们选择了3，3 '，5，5'-四甲基联苯胺（TMB）和2，2-连氮双（3-乙基苯并噻唑-6-磺酸）（AzBTS），它们在氧化后在水溶液中显蓝色（TMB）或绿色（AzBTS）。[13这些染料通常在各种生物测定中用作辣根过氧化物酶（HRP）底物，并且最近它们已被用于证明氧化铁纳米颗粒的过氧化物酶样活性。[15]然而，在这些过氧化物酶催化的反应中，需要过氧化氢（H2 O2）作为电子受体或氧化剂。相比之下，我们发现DNC催化两种物质的快速氧化（在几分钟内）。
Unique catalytic activities have been reported for nanoscale materials in recent years.[1] These size-dependent properties, which are often absent in the bulk materials, are the basis for the design of novel catalysts with multiple applications in energy storage, chemical synthesis, and biomedical applications.[2, 3] Cerium oxide has been extensively used in catalytic converters for automobile exhaust systems, as an ultraviolet absorber, and as an electrolyte for fuel cells.[4–7] Most recently, it has been found that cerium oxide nanoparticles (nanoceria) possess antioxidant activity at physiological pH values, and the potential use of these materials in biomedical applications, such as protection against radiation damage, oxidative stress, and inflammation, has been reported.[8–12] The ability of these nanoparticles to act as an antioxidant resides on their ability to reversibly switch from Ce3+ to Ce4+.[11] Furthermore, the synthesis of biocompatible dextran-coated nanoceria (DNC) and its enhanced stability in aqueous solution has been recently reported.[12]Herein, we report that nanoceria has an intrinsic oxidaselike activity at acidic pH values, as it can quickly oxidize a series of organic substrates without any oxidizing agent (eg hydrogen peroxide). The observed activity is not only pH-dependent but is also dependent on the size of the cerium oxide nanoparticles as well as the thickness of the polymer coating. On the basis of these findings, we have designed an immunoassay in which folate-conjugated cerium oxide nanoparticles provide dual functionality by binding to folateexpressing cancer cells and facilitating detection by catalytic oxidation of sensitive colorimetric substrates (dyes). The unique pH-dependent oxidase-like activity of cerium oxide nanoparticles in aqueous media makes them a powerful tool for a wide range of potential applications in biotechnology and environmental chemistry. For our first set of experiments, we investigated if a DNC preparation [12] could facilitate the oxidation of a series of organic dyes at low pHvalues. In these experiments, we selected 3, 3о, 5, 5о-tetramethylbenzidine (TMB) and 2, 2-azinobis (3-ethylbenzothizoline-6-sulfonic acid)(AzBTS), which upon oxidation develop either a blue (TMB) or green (AzBTS) color in aqueous solution.[13, 14] These dyes are typically used as horseradish peroxidase (HRP) substrates in various bioassays, and most recently they have been used to demonstrate the peroxidase-like activity of iron oxide nanoparticles.[15] However, in these peroxidase-catalyzed reactions, hydrogen peroxide (H2O2) is required as the electron acceptor or oxidizing agent. In contrast, we have found that DNC catalyzes the fast oxidation (within minutes) of both
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影响因子：
1.5
作者：
Henriquez, C;Aliaga, C;Lissi, E
通讯作者：
Lissi, E
影响因子：
15
作者：
White, Meghann A.;Johnson, Jeremiah A.;Turro, Nicholas J.
通讯作者：
Turro, Nicholas J.
影响因子：
10.8
作者：
Niu, Jianli;Azfer, Asim;Kolattukudy, Pappachan E.
通讯作者：
Kolattukudy, Pappachan E.
影响因子：
4.8
作者：
Bisaglia, Marco;Mammi, Stefano;Bubacco, Luigi
通讯作者：
Bubacco, Luigi
影响因子：
29.4
作者：
Laberty-Robert, Christel;Long, Jeffrey W.;Rolison, Debra R.
通讯作者：
Rolison, Debra R.