Highly sensitive and efficient fluorescent sensing for Hg2+ detection based on triple-helix molecular switch and exonuclease III-assisted amplification
Highly sensitive and efficient fluorescent sensing for Hg2+ detection based on triple-helix molecular switch and exonuclease III-assisted amplification
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基于三螺旋分子开关和核酸外切酶 III 辅助扩增的高灵敏度、高效荧光传感 Hg2 检测
DOI：
10.1016/j.aca.2022.339751
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发表时间：
2022
影响因子：
6.2
通讯作者：
Jinquan Liu
中科院分区：
文献类型：
--
作者：
Miao Zhong;Shengyuan Yang;Lei Chen;Chen Liu;Jiao Shi;Hao Liang;Xilin Xiao;Le Li;Jinquan Liu
本研究利用三螺旋分子开关（THMS）和外切酶III （Exo III）辅助信号放大技术，开发了一种简单、高灵敏度、高效检测Hg2+的新型荧光传感技术。本研究利用THMS的特殊结构，实现高效的荧光猝灭和优异的信号单元变换，完成信号FAM的输出。在没有Hg2+的情况下，含有胸腺嘧啶富（T-rich） ssDNA链的发夹探针（hairpin probe， HP）可以诱导THMS解离，使FAM远离BHQ1，荧光强度增加。然而，Hg2+可以与胸腺嘧啶(T)碱基结合形成具有T-Hg2+-T结构的dsDNA，刺激Exo III从钝的3 ' -末端消化到5 ' -末端，导致Hg2+从dsDNA中释放出来。释放的Hg2+可以启动下一个循环，允许大量发夹探针被Exo III切割形成ssDNA。这些ssDNA可以抑制THMS的开关解离，导致荧光信号急剧下降。这允许在低至1.04 pM的浓度下高度敏感地检测Hg2+。该传感器具有0.01 ~ 50 nM的线性检测范围，可用于湘江水和自来水中Hg2+的检测。这些结果表明，所提供的荧光传感在环境和食品监测中具有良好的应用前景。
Here, a novel fluorescent sensing for simple, highly sensitive and efficient detection of Hg2+was developed as joint result of triple-helix molecular switch (THMS) and exonuclease III (Exo III)-assisted signal amplification. In this study, the special structure of THMS was used to realize efficient fluorescence quenching and excellent signal unit transformation to complete the output of signal FAM. In the absence of Hg2+, hairpin probe (HP) containing thymine-rich (T-rich) ssDNA strand can induce the dissociation of the THMS, causing FAM far away from BHQ1 and increasing fluorescence intensity. Nevertheless, Hg2+could bind to the thymine (T) base to form the dsDNA with T-Hg2+-T structure that stimulates Exo III to digest it from the blunt 3′-terminus to 5′-terminus, causing Hg2+to be released from the dsDNA. The released Hg2+could initiate the next cycling, allowing a large number of hairpin probes to be cleaved by Exo III to form ssDNA. These ssDNA could inhibit the switch dissociation of THMS, causing a dramatic decrease in the fluorescence signal. This allowed for the highly sensitive detection of Hg2+at concentrations as low as 1.04 pM. In addition, the sensing showed a linear detection range of 0.01–50 nM and was used for the assay of Hg2+in real samples of Xiangjiang river water and tap water. These results showed that the provided fluorescent sensing has a good application prospect in environmental and food monitoring.