Sensitive dual DNAzymes-based sensors designed by grafting self-blocked G-quadruplex DNAzymes to the substrates of metal ion-triggered DNA/RNA-cleaving DNAzymes.
Sensitive dual DNAzymes-based sensors designed by grafting self-blocked G-quadruplex DNAzymes to the substrates of metal ion-triggered DNA/RNA-cleaving DNAzymes.
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DOI：
10.1016/j.bios.2012.06.011
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发表时间：
2012-10
影响因子：
12.6
通讯作者：
Qi Zhang;Yang Cai;Hui Li;Deming Kong;Han-xi Shen
中科院分区：
文献类型：
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作者：
Qi Zhang;Yang Cai;Hui Li;Deming Kong;Han-xi Shen
基于金属离子特异性切割DNA/RNA的DNA酶和G-四链体DNA酶，提出了一种通用的无标记金属离子传感器设计策略。在该策略中，切割DNA/RNA的DNAzyme的底物链被设计为分子内茎环结构，富含G的序列被笼在双链茎中，不能形成催化活性的G-四链体DNAzyme。金属离子触发的底物链的切割可以导致富含G的序列的释放和随后催化的G-四链体DNA酶的形成。G-quadruplex DNAzyme的自封闭机制为传感系统提供了低背景信号。DNA/RNA切割DNAzyme和G-四链体DNAzyme两者的信号扩增为传感系统提供了高水平的灵敏度。该传感器设计策略可用于具有报道的特异性DNA/RNA切割DNA酶的金属离子，并可扩展用于具有独特性质的金属离子。作为实例，设计了基于双DNA酶的Cu 2+、Pb 2+和Hg 2+传感器。这些“开启”比色传感器可以简单地检测Cu 2+，Pb 2+和Hg 2+，具有高水平的灵敏度和选择性，检测限分别为4 nM，14 nM和4 nM。
A universal label-free metal ion sensor design strategy was developed on the basis of a metal ion-specific DNA/RNA-cleaving DNAzyme and a G-quadruplex DNAzyme. In this strategy, the substrate strand of the DNA/RNA-cleaving DNAzyme was designed as an intramolecular stem–loop structure, and a G-rich sequence was caged in the double-stranded stem and could not form catalytically active G-quadruplex DNAzyme. The metal ion-triggered cleavage of the substrate strand could result in the release of the G-rich sequence and subsequent formation of a catalytic G-quadruplex DNAzyme. The self-blocking mechanism of the G-quadruplex DNAzyme provided the sensing system with a low background signal. The signal amplifications of both the DNA/RNA-cleaving DNAzyme and the G-quadruplex DNAzyme provided the sensing system with a high level of sensitivity. This sensor design strategy can be used for metal ions with reported specific DNA/RNA-cleaving DNAzymes and extended for metal ions with unique properties. As examples, dual DNAzymes-based Cu2+, Pb2+and Hg2+sensors were designed. These “turn-on” colorimetric sensors can simply detect Cu2+, Pb2+and Hg2+with high levels of sensitivity and selectivity, with detection limits of 4nM, 14nM and 4nM, respectively.