School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Normal University, Xinxiang, Henan, 453007, PR China.
School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Normal University, Xinxiang, Henan, 453007, PR China.
Colloids Surf B Biointerfaces. 2018 Jul 1;167:150-155. doi: 10.1016/j.colsurfb.2018.04.004. Epub 2018 Apr 5.
Despite their practical applications, Ag ions are environmental pollutants and affect human health. So the effective detection methods of Ag ions are imperative. Herein, we developed a simple, sensitive, selective, and cost-effective fluorescence polarization sensor for Ag detection in aqueous solution using thiol-DNA-functionalized gold nanoparticles (AuNPs). In this sensing strategy, Ag ions can specifically interact with a cytosine-cytosine (CC) mismatch in DNA duplexes and form stable metal-mediated cytosine-Ag-cytosine (C-Ag-C) base pairs. The formation of the C-Ag-C complex results in evident changes in the molecular volume and fluorescence polarization signal. To achieve our aims, we prepared two complementary DNA strands containing C-base mismatches (probe A: 5'-SH-A-TACCACTCCTCAC-3' and probe B: 5'-TCCTCACCAGTCCTA-FAM-3'). The stable hybridization between probe A and probe B occurs with the formation of the C-Ag-C complex in the presence of Ag ions, leading to obvious fluorescence quenching in comparison to the system without AuNP enhancement. The assay can be used to identify nanomolar levels of Ag within 6 min at room temperature, and has extremely high specificity for Ag, even in the presence of higher concentrations of interfering metal ions. Furthermore, the sensor was successfully applied to the detection of Ag ions in environmental water samples and showed excellent selectivity and high sensitivity, implying its promising application in the future.
尽管银离子具有实际应用价值，但它们也是环境污染物，会影响人类健康。因此，开发有效的银离子检测方法势在必行。在此，我们使用巯基-DNA 功能化的金纳米粒子 (AuNPs) 开发了一种简单、灵敏、选择性和具有成本效益的用于水溶液中银检测的荧光偏振传感器。在这种传感策略中，银离子可以特异性地与 DNA 双链体中的胞嘧啶-胞嘧啶 (CC) 错配相互作用，并形成稳定的金属介导的胞嘧啶-银-胞嘧啶 (C-Ag-C) 碱基对。C-Ag-C 配合物的形成导致分子体积和荧光偏振信号的明显变化。为了达到我们的目的，我们制备了两条含有 C 碱基错配的互补 DNA 链（探针 A：5'-SH-A-TACCACTCCTCAC-3'和探针 B：5'-TCCTCACCAGTCCTA-FAM-3'）。在存在银离子的情况下，探针 A 和探针 B 之间稳定的杂交会导致 C-Ag-C 配合物的形成，与 AuNP 增强前的系统相比，会导致明显的荧光猝灭。该测定法可在室温下在 6 分钟内识别纳摩尔级别的银，并且对银具有极高的特异性，即使在存在较高浓度的干扰金属离子时也是如此。此外，该传感器成功应用于环境水样中银离子的检测，表现出优异的选择性和高灵敏度，表明其在未来具有广阔的应用前景。
