Simple and highly sensitive molecular beacon probe based on target-induced structure-switching DNA for mercury(II) detection
Simple and highly sensitive molecular beacon probe based on target-induced structure-switching DNA for mercury(II) detection
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DOI：
10.1039/c3ay41610k
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发表时间：
2013-11
影响因子：
3.1
通讯作者：
Mei Li;Yong Huang;Shulin Zhao
中科院分区：
文献类型：
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作者：
Mei Li;Yong Huang;Shulin Zhao
设计了一种简单且高灵敏度的分子信标 (MB) 探针，该探针基于靶标诱导的 DNA 发夹构象转换与胸腺嘧啶-Hg2+-胸腺嘧啶 (T-Hg2+-T) 配位化学的耦合，用于测定汞 (II) (Hg2+)。在此 MB 中，DNA 发夹包含 6 个碱基对的茎，包围一个 27 核苷酸 (nt) 环，并在 3' 端有一个额外的 12 nt 粘性末端。从 3' 端算起的第 12 个碱基用 4-(4'-二甲氨基苯基偶氮) 苯甲酸 (DABCYL) 猝灭剂标记，5' 端用荧光团荧光素酰胺 (FAM) 标记。在没有 Hg2+ 的情况下，DNA 发夹呈闭合形式，导致荧光猝灭。在目标分析物存在的情况下，Hg2+介导的碱基对诱导从粘性末端到打开发夹的构象变化；荧光团和猝灭剂彼此远离，导致荧光恢复。动态浓度范围为 0.5 至 50 nM Hg2+，在 3σ 水平下检测限为 0.3 nM。该检测策略对 Hg2+ 相对于其他环境相关金属离子具有高选择性。所开发的方法非常简单，只需一步反应即可实现Hg2+的测定。
A simple and highly sensitive molecular beacon (MB) probe, based on coupling target-induced conformational switching of DNA hairpins with thymine–Hg2+–thymine (T–Hg2+–T) coordination chemistry, was designed for the determination of mercury(II) (Hg2+). In this MB, the DNA hairpins contain a stem of 6 base pairs enclosing a 27 nucleotide (nt) loop and an additional 12 nt sticky end at the 3′ end. The twelfth base from the 3′ end was labeled with a quencher of 4-(4′-dimethylaminophenylazo) benzoic acid (DABCYL), and the 5′ end was labeled with a fluorophore fluorescein amidite (FAM). In the absence of Hg2+, the DNA hairpin is in a closed form resulting in fluorescence quenching. In the presence of the target analyte, Hg2+-mediated base pairs induce the conformational change from the sticky end to open the hairpins; the fluorophore and the quencher are moved away from each other, leading to the restoration of fluorescence. The dynamic concentration range was from 0.5 to 50 nM Hg2+ with a detection limit of 0.3 nM at the 3σ level. The assay strategy afforded high selectivity for Hg2+ against other environmentally related metal ions. The developed method is very simply, only requiring a one-step reaction to realize the assay of Hg2+.