Increasing the antioxidant capacity of ceria nanoparticles with catechol-grafted poly(ethylene glycol).
Increasing the antioxidant capacity of ceria nanoparticles with catechol-grafted poly(ethylene glycol).
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用儿茶酚接枝聚乙二醇提高二氧化铈纳米颗粒的抗氧化能力。
DOI：
10.1039/d2tb00779g
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Colvin,VickiL
中科院分区：
文献类型：
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作者：
Hu,Yue;Zhang,Qingbo;Garcia-Rojas,Daniel;Ling,Vivian;Masterson,CaitlinM;Bi,Yidan;Xiao,Zhen;Guo,Xiaoting;Villanova,Jake;Dunn,Joshua;Colvin,VickiL
纳米CeO_2由于其大量的Ce(III)含量和反应后从Ce(IV)中回收Ce(III)的可能性，是一种出色的抗氧化剂。在这里，我们使用反应性聚合物表面涂层来增加胶体稳定的纳米颗粒(例如纳米晶体)的Ce(III)含量。儿茶酚接枝的聚乙二醇类聚合物具有不同的长度和结构，可产生在各种水介质中不聚集的材料。CeO2表面的Ce(IV)结合和氧化儿茶酚功能，产生表面氧化儿茶酚的深红色象征，X射线光电子能谱(XPS)显示伴随着Ce(III)的增加。CeO2还原的程度敏感地取决于涂层聚合物的结构；小而紧密的聚合物链在纳米颗粒表面以高密度堆积，产生最多的Ce3+。表面还原增加的纳米颗粒，通过其光学吸收的强度和聚合物接枝密度的热重测量来量化，根据标准的TEAC抗氧化剂测定，是更有效的抗氧化剂。对于相同的核心成分，通过调整反应性表面涂层的长度和结构，纳米粒子的抗氧化能力可以增加一个数量级以上。
Ceria nanoparticles are remarkable antioxidants due to their large cerium(III) content and the possibility of recovering cerium(III) from cerium(IV) after reaction. Here we increase the cerium(III) content of colloidally stable nanoparticles (e.g., nanocrystals) using a reactive polymeric surface coating. Catechol-grafted poly(ethylene glycols) (PEG) polymers of varying lengths and architectures yield materials that are non-aggregating in a variety of aqueous media. Cerium(IV) on the ceria surface both binds and oxidizes the catechol functionality, generating a dark-red colour emblematic of surface-oxidized catechols with a concomitant increase in cerium(III) revealed by X-ray photoemission spectroscopy (XPS). The extent of ceria reduction depends sensitively on the architecture of the coating polymer; small and compact polymer chains pack with high density at the nanoparticle surface yielding the most cerium(III). Nanoparticles with increased surface reduction, quantified by the intensity of their optical absorption and thermogravimetric measures of polymer grafting densities, were more potent antioxidants as measured by a standard TEAC antioxidant assay. For the same core composition nanoparticle antioxidant capacities could be increased over an order of magnitude by tailoring the length and architecture of the reactive surface coatings.