Oxidative quenching and degradation of polymer-encapsulated quantum dots: new insights into the long-term fate and toxicity of nanocrystals in vivo.
Oxidative quenching and degradation of polymer-encapsulated quantum dots: new insights into the long-term fate and toxicity of nanocrystals in vivo.
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DOI：
10.1021/ja8040477
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发表时间：
2008-08-20
影响因子：
15
通讯作者：
Nie, Shuming
中科院分区：
文献类型：
--
作者：
Mancini, Michael C.;Kairdolf, Brad A.;Smith, Andrew M.;Nie, Shuming
我们报道了活性氧物质（ROS）对聚合物包覆的量子点的猝灭和化学降解作用。活性氧物质是一类由细胞代谢产生的含氧分子，参与正常生理过程以及诸如氧化信号传导、癌症和动脉粥样硬化等疾病过程。一项主要的新发现是，中性形式的次氯酸（HOCl）在降解封装的量子点方面特别有效，这是由于其在生理条件下尺寸小、呈中性电荷、半衰期长以及反应动力学快。因此，像HOCl和过氧化氢（H₂O₂）这样的小分子和中性分子被认为能够扩散穿过聚合物包覆层，导致量子点表面的硫或硒原子发生化学氧化。这种“蚀刻”过程首先产生晶格结构缺陷（这会导致荧光猝灭），然后产生可溶性金属（例如镉和锌）和硫族化物（例如硫和硒）物质。我们还发现，在量子点溶解之前就会发生显著的荧光猝灭，并且局部表面缺陷可以通过紫外线照射进行修复或“退火”。这些结果对于半导体纳米晶体在体内的长期命运和潜在毒性具有重要意义。
We report quenching and chemical degradation of polymer-coated quantum dots by reactive oxygen species (ROS), a group of oxygen-containing molecules that are produced by cellular metabolism and are involved in both normal physiological and disease processes such as oxidative signaling, cancer, and atherosclerosis. A major new finding is that hypochlorous acid (HOCl) in its neutral form is especially potent in degrading encapsulated QDs, due to its small size, neutral charge, long half-life, and fast reaction kinetics under physiologic conditions. Thus, small and neutral molecules such as HOCl and hydrogen peroxide (H2O2) are believed to diffuse across the polymer coating layer, leading to chemical oxidation of sulfur or selenium atoms on the QD surface. This “etching” process first generates lattice structural defects (which cause fluorescence quenching), and then produces soluble metal (e.g., cadmium and zinc) and chalcogenide (e.g., sulfur and selenium) species. We also find that significant fluorescence quenching occurs before QD dissolution, and that localized surface defects can be repaired or “annealed” by UV light illumination. These results have important implications regarding the long-term fate and potential toxicity of semiconductor nanocrystals in-vivo.
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影响因子：
46.9
作者：
Lidke, DS;Nagy, P;Jovin, TM
通讯作者：
Jovin, TM
DOI：
10.1161/01.atv.0000163846.51473.09
发表时间：
2005-07-01
影响因子：
8.7
作者：
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作者：
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通讯作者：
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影响因子：
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作者：
Chan, WCW;Nie, SM
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影响因子：
11.5
作者：
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通讯作者：
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