Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5009198 | Sensors and Actuators B: Chemical | 2017 | 8 Pages |
Abstract
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 3â²-hydroxyl terminus of dsDNA with a blunt 3â² 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 1.5Â nM. This sensor exhibits high selectivity against other metal ions, and it works well for real samples.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Lili Yu, Wei Lan, Hui Xu, Hou Chen, Liangjiu Bai, Wenxiang Wang,