Xu Laifang, Hao Junjie, Yi Tao, Xu Yinyin, Niu Xiaoying, Ren Cuiling, Chen Hongli, Chen Xingguo
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, China; Department of Chemistry, Lanzhou University, Lanzhou, China.
Electrophoresis. 2015 Mar;36(6):859-66. doi: 10.1002/elps.201400509. Epub 2015 Feb 27.
A good understanding of the mechanism of interaction between quantum dots (QDs) and heavy metal ions is essential for the design of more effective sensor systems. In this work, CE was introduced to explore how l-cysteine-capped-CdTe QDs (l-cys-CdTe QDs) interacts with Hg(2+) . The change in electrophoretic mobility can synchronously reflect the change in the composition and property of QDs. The effects of the free and capping ligands on the system are discussed in detail. ESI-MS, dynamic light scattering (DLS), zeta potential, and fluorescence (FL) were also applied as cooperative tools to study the interaction mechanism. Furthermore, the interaction mechanism, which principally depended on the concentration of Hg(2+) , was proposed reasonably. At the low concentration of Hg(2+) , the formation of a static complex between Hg(2+) and the carboxyl and amino groups of l-cys-CdTe QDs surface was responsible for the FL quenching. With the increase of Hg(2+) concentration, the capping l-cys was stripped from the surface of l-cys-CdTe QDs due to the high affinity of Hg(2+) to the thiol group of l-cys. Our study demonstrates that CE can reveal the mechanism of the interaction between QDs and heavy metal ions, such as FL quenching.
深入了解量子点（QDs）与重金属离子之间的相互作用机制对于设计更有效的传感器系统至关重要。在这项工作中，引入毛细管电泳（CE）来探究L-半胱氨酸包覆的碲化镉量子点（L-cys-CdTe QDs）与Hg(2+) 之间的相互作用。电泳迁移率的变化能够同步反映量子点组成和性质的变化。详细讨论了游离配体和封端配体对该体系的影响。电喷雾电离质谱（ESI-MS）、动态光散射（DLS）、zeta电位和荧光（FL）也被用作辅助工具来研究相互作用机制。此外，合理地提出了主要依赖于Hg(2+) 浓度的相互作用机制。在低浓度Hg(2+) 时，Hg(2+) 与L-cys-CdTe QDs表面的羧基和氨基形成静态配合物导致荧光猝灭。随着Hg(2+) 浓度的增加，由于Hg(2+) 对L-cys硫醇基团的高亲和力，封端的L-cys从L-cys-CdTe QDs表面被剥离。我们的研究表明，毛细管电泳能够揭示量子点与重金属离子之间的相互作用机制，如荧光猝灭。
