Fluorometric determination of mercury(II) via a graphene oxide-based assay using exonuclease III-assisted signal amplification and thymidine-Hg(II)-thymidine interaction
Fluorometric determination of mercury(II) via a graphene oxide-based assay using exonuclease III-assisted signal amplification and thymidine-Hg(II)-thymidine interaction
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使用核酸外切酶 III 辅助信号放大和胸苷-Hg(II)-胸苷相互作用，通过基于氧化石墨烯的测定法荧光测定汞 (II)
DOI：
10.1007/s00604-019-3332-x
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发表时间：
2019-04-01
影响因子：
5.7
通讯作者：
Lu, Fangguo
中科院分区：
文献类型：
--
作者：
Ning, Yi;Hu, Jue;Lu, Fangguo
本文提出了一种高灵敏度、高选择性的荧光光度法测定汞（II）。其基于（a）使用氧化石墨烯（GO）作为羧基荧光素（FAM）的荧光猝灭剂，和（B）Hg（II）触发的核酸外切酶III（Exo III）对新形成的具有平端3-羟基末端的核酸序列的切割，导致信号放大。使用两种DNA探针，即部分互补的捕获探针（CP）和辅助探针（HP）。在不存在Hg（II）的情况下，FAM标记的发夹（信号探针，SP）通过堆叠相互作用吸附到GO的表面上。CP阻断HP与SP结合的释放。这导致标记物的绿色荧光淬灭。加入Hg（II）后，CP的线性结构由于形成胸苷-Hg（II）-胸苷双链体而转化为发夹结构。HP从CP/HP杂合体中释放，并且这导致SP从GO中释放并且荧光被恢复。通过使用Exo III辅助的HP靶向和再循环，信号被强烈放大。因此，Hg（II）可以通过荧光的强烈增加来检测。该方法在0.1至30 nM Hg（II）浓度范围内具有线性响应，检测限为10 pM。应用该方法测定了3种中草药中汞的含量。
A highly sensitive and selective fluorometric method is described for determination of mercury(II). It is based on (a) the use of graphene oxide (GO) acting as a quencher of the fluoresence of the carboxy-fluorescein (FAM), and (b) of Hg(II)-triggered cleavage of the newly formed nucleic acid sequences harbored blunt 3-hydroxyl termini by exonuclease III (Exo III) that leads to signal amplification. Two DNA probes are used, viz. a capture probe (CP) and a help probe; HP) that is partially complementary. In the absence of Hg(II), the FAM-labeled hairpin (signal probe, SP) is adsorbed onto the surface of GO via -stacking interactions. CP blocks the release of the HP for binding to SP. This results in quenching of the green fluorescence of the label. Upon addition of Hg(II), the linear structure of CP is converted to a hairpin structure due to the formation of thymidine-Hg(II)-thymidine duplexes. HP is released from the CP/HP hybrids, and this causes SP to be released from from GO and fluorescence to be recovered. The signal is strongly amplified by using Exo III-assisted targeting and recycling of HP. Hence, Hg(II) can be detected via the strong increase in fluorescence. The method has a linear response in the 0.1 to 30nM Hg(II) concentration range and a 10 pM detection limit. It was applied to the determination of Hg(II) in three (spiked) Chinese medicines.