Metallo-Toehold-Activated Catalytic Hairpin Assembly Formation of Three-Way DNAzyme Junctions for Amplified Fluorescent Detection of Hg2+
Metallo-Toehold-Activated Catalytic Hairpin Assembly Formation of Three-Way DNAzyme Junctions for Amplified Fluorescent Detection of Hg2+
复制标题
金属立足点激活催化发夹组装形成三路 DNAzyme 连接，用于 Hg2 的放大荧光检测
DOI：
10.1021/acsami.6b13717
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发表时间：
2017-02-22
影响因子：
9.5
通讯作者：
Xiang, Yun
中科院分区：
文献类型：
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作者：
Li, Xin;Xie, Jiaqing;Xiang, Yun
由于He 2+对环境和人体具有不可逆的毒性作用，因此发展可靠、灵敏、高选择性的检测方法具有重要意义。基于金属支点触发、催化发夹组装（CHA）形成的三向DNA酶连接对信号的显著放大作用，我们构建了一个高选择性、高灵敏度的荧光传感体系，用于不同环境水样中Hg 2+的测定。Hg 2+离子的存在可导致T-He 2 +-T碱基错配的金属支点的产生，其触发含有发夹的三个分裂DNA酶的催化组装，从而在结合到荧光猝灭的底物序列时形成许多Mg 2+依赖的DNA酶连接结构。然后，Mg 2+离子循环切割Mg 2+依赖性DNA酶的荧光猝灭底物序列，以产生显著增强的荧光信号，用于在低4.5 pM水平下灵敏地检测He 2+。开发的传感方法提供了高选择性对目标He 2+超过其他可能的竞争金属离子，由于特定的T-Hg 2 +-T桥结构的化学在金属支点域，和可靠的检测加标Hg 2+在环境相关的水样与此方法也得到验证。考虑到触发和组装序列的核酸性质，所开发的方法因此具有很大的潜力，用于设计新的无酶信号放大策略，以实现不同的DNA和RNA靶标的高灵敏度测定。
Because of their irreversible toxicological impacts on the environment and human body, the development of reliable and sensitive He2+ detection methods with high selectivity is of great significance. On the basis of the substantial signal amplification by metallo-toehold-triggered, catalytic hairpin assembly (CHA) formation of three-way DNAzyme junctions, we have constructed a highly selective and sensitive fluorescent sensing system for the determination of Hg2+ in different environmental water samples. The presence of the target Hg2+ ions can lead to the generation of T-He2+-T base mismatched metallo-toeholds, which trigger the catalytic assembly of three split-DNAzyme containing hairpins to form many Mg2+-dependent DNAzyme junction structures upon binding to the fluorescently quenched substrate sequences. The Mg2+ ions then cyclically cleave the fluorescently quenched substrate sequences of the Mg2+-dependent DNAzymes to generate drastically enhanced fluorescent signals for sensitively detecting He2+ at the low 4.5 pM level. The developed sensing method offers high selectivity toward the target He2+ over other possible competing metal ions due to the specific T-Hg2+-T bridge structure chemistry in the metallo-toehold domain, and reliable detection of spiked Hg2+ in environmentally relevant water samples with this method is also verified. Considering the nucleic acid nature of the trigger and assembly sequences, the developed approach thus holds great potentials for designing new enzyme-free signal amplification strategies to achieve highly sensitive determination of different DNA and RNA targets.