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A dual-cycling biosensor for the target DNA detection based on the toehold-mediated strand displacement reaction and exonuclease III assistant amplification

Abstract

Sensitive detection of the disease-related DNA is of great significance for early and accurate diagnosis and therapy. To achieve this aim, we constructed a dual-cycling amplification biosensor for the target oligonucleotide detection. Based on the toehold-mediated strand displacement reaction (TSDR), target DNA competitively hybridized with the assistant DNA which previously formed the duplex complex with the trigger DNA, and the trigger DNA was released. Exonuclease III (Exo III) would specially hydrolyze the assistant DNA in the new duplex DNA to free the target for a new cycle. Similarly, based on TSDR and Exo III assistant amplification, released trigger DNA would repeatedly open the G-quadruplex hairpins and promote the generation of numerous G-quadruplex sequences. Then, the fluorescence intensity of Thioflavin T (ThT) would present apparent enhancement due to the formation of G-quadruplex/ThT complex. The commercially available ThT is economical and low toxic. More importantly, owing to its satisfactory water solubility, ThT effectively avoids the introduction of organic solvents. There was no need for expensive modification through the whole process. The proposed method displayed high distinction efficiency towards target DNA against mismatched DNA. Additionally, the linear range of this strategy was 0.2 - 10 nM, and the detection limit was 0.04 nM. Besides, this sensor can be applied in human serum with satisfactory results.

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Publication details

The article was received on 31 Dec 2017, accepted on 08 Feb 2018 and first published on 08 Feb 2018


Article type: Paper
DOI: 10.1039/C7NJ05191C
Citation: New J. Chem., 2018, Accepted Manuscript
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    A dual-cycling biosensor for the target DNA detection based on the toehold-mediated strand displacement reaction and exonuclease III assistant amplification

    Y. Ling, X. F. Zhang, X. H. Chen, L. Liu, X. H. Wang, D. S. Wang, N. Li and H. Q. Luo, New J. Chem., 2018, Accepted Manuscript , DOI: 10.1039/C7NJ05191C

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