期刊
SENSORS AND ACTUATORS B-CHEMICAL
卷 248, 期 -, 页码 411-418出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.snb.2017.03.153
关键词
Mercury ions; Label-free detection; Toehold binding; Exonuclease III assisted target recycling; Hybridization chain reaction
资金
- National Natural Science Foundation of China [51573075, 21404051, 21404052]
- Natural Science Foundation of Shandong Province [ZR2016BM27, ZR2014BQ016, BS2014CL040]
- Program for Scientific Research Innovation Team in Colleges and universities of Shandong Province
We constructed a fluorometric and sensitive analysis of mercury (II) based on toehold-mediated strand displacement reaction, exonuclease III (Exo III) assisted target recycling, hybridization chain reaction (HCR), fluorescence intercalator SYBR Green I (SG) and grapheme oxide (GO). Firstly, toehold-mediated strand displacement reaction was constructed by using thymine-Hg2+-thymine (T-Hg2+-T) recognition mechanism between the helper hairpin DNA and assisted DNA. And then, the Exo III disintegrated the double-stranded DNA (dsDNA) by catalyzing the gradual removal of mononucleotides from 3'-hydroxyl terminus of dsDNA with a blunt 3' terminus. It resulted in the target and assisted DNA recycling and released a trigger strand DNA at the same time. Finally, the trigger strand DNA initiated the hybridization chain reaction (HCR), forming long double helices, which achieved a secondary amplification due to the continuous target recycling, trigger strand DNA release and HCR. The number of T-T mismatches, the concentration of SG, Exo III and GO, the incubation time of Exo III were all optimized. Under the optimized condition, the limit of detection for Hg2+ can be down to 7.37 pM with a linear range from 0 to 1.5 nM. This sensor exhibits high selectivity against other metal ions, and it works well for real samples. (C) 2017 Elsevier B.V. All rights reserved.
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