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Anal Chim Acta. 2018 Dec 14;1038:126-131. doi: 10.1016/j.aca.2018.07.011. Epub 2018 Jul 6.

Aptamer proximity recognition-dependent strand translocation for enzyme-free and amplified fluorescent detection of thrombin via catalytic hairpin assembly.

Author information

1
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
2
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yunatswu@swu.edu.cn.

Abstract

By coupling a new aptamer proximity recognition-dependent strand translocation strategy with catalytic hairpin assembly (CHA) signal amplification, we have developed a simple and sensitive method for detecting thrombin in human serums. Simultaneous binding of two engineered aptamer probes to the thrombin target significantly increases the local concentrations of the two probes and facilitates the translocation of a ssDNA strand from one of the probes to the other through toehold mediated strand displacement. Such a strand translocation leads to the generation of a ssDNA tail in the aptamer sequence for subsequent initiation of the assembly of two fluorescently quenched hairpins into many DNA duplexes via CHA. The formation of the DNA duplexes thus results in significant fluorescence recovery for amplified detection of thrombin down to 8.3 pM. The developed method is highly selective to the thrombin target against other interference proteins due to the dual recognition mode, and can be employed to monitor thrombin in human serum samples. With the advantage of simplicity, sensitivity and selectivity, this method can be a universal non-enzymatic and nanomaterial-free amplified sensing platform for detecting different protein molecules.

KEYWORDS:

Aptamer; Catalytic hairpin assembly; Strand translocation; Thrombin

PMID:
30278894
DOI:
10.1016/j.aca.2018.07.011
[Indexed for MEDLINE]

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