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Enzyme-free fluorescent detection of microcystin-LR using hairpin DNA-templated copper nanoclusters as signal indicator

journal contribution
posted on 2019-09-01, 00:00 authored by Yanli Zhang, Zhenyu Zhu, Xia Teng, Yanqiong Lai, Shaofu Pu, Pengfei Pang, Hongbin Wang, Chun Yang, Colin BarrowColin Barrow, Wenrong YangWenrong Yang
Microcystin-LR (MC-LR) is a potent hepatotoxin that is often associated with blooms of cyanobacteria. The analysis of trace MC-LR plays important role in environmental and health fields. Herein, we developed a low-cost and enzyme-free detection method of MC-LR by using hairpin DNA-templated copper nanoclusters (hpDNA-CuNCs) as fluorescent probe. The hpDNA-template was designed and fabricated by a MC-LR aptamer loop and a double strand stem, which can specifically recognize target MC-LR with strong affinity. The AT-rich and complementary double strand stem serves as a template for the formation of CuNCs. The formed fluorescent sensing probe of hpDNA-CuNCs exhibits maximum emission wavelength at 575 nm. Upon the addition of target MC-LR into the hpDNA-CuNCs, we observed fluorescence was quenched considerably due to the high affinity between MC-LR and hpDNA aptamer strand loop, which indicated a conformational change of hairpin probe from the stem-loop DNA structure to single-stranded DNA. Then, the change of fluorescence intensity can be used to monitor the concentration of MC-LR from 0.005 to 1200 μg L-1 with a detection limit of 0.003 ng L-1. Compared with the previous reports, this method does not require complex DNA sequence design, fluorescence dye label and sophisticated experimental techniques. Moreover, the target MC-LR in real water samples has been detected.







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Amsterdam, The Netherlands





Publication classification

C1 Refereed article in a scholarly journal

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2019, Esevier B.V.