The isolation of a DNA aptamer to develop a fluorescent aptasensor for the thiamethoxam pesticide

Luo, Y;Jin, ZY;Wang, JN;Ding, P;Pei, RJ

[Luo, Yu; Jin, Ziying; Wang, Jine; Ding, Pi; Pei, Renjun] Chinese Acad Sci, Suzhou Inst Nanotech & Nanobion, CAS Key Lab Nanobio Interface, Suzhou 215123, Peoples R China.
[Luo, Yu] Univ Sci & Technol China, Nano Sci & Technol Inst, Suzhou 215123, Peoples R China.
[Jin, Ziying] Xian Jiaotong Liverpool Univ, Dept Biol Sci, Suzhou 215123, Peoples R China.

ANALYST

Volume:146 Issue:6Pages:1986-1995

DOI:10.1039/d0an01967d

Publication Year:2021

CAS JCR:2区

ESI Discipline:CHEMISTRY

Latest Impact Factor:4.616

Document Type:Journal Article

Identifier:http://hdl.handle.net/20.500.12791/000441

Abstract

Aptamers, which are called chemical antibodies for their high affinity and specificity to targets, have great potential as analytical tools to detect pesticides. In this work, a DNA aptamer for thiamethoxam was isolated by an improved SELEX (systematic evolution of ligands by exponential enrichment) strategy, in which the ssDNA library was fixed on streptavidin-agarose beads through a short biotin labeled complementary strand. After 13 rounds of selection, the random ssDNA pool was successfully enriched. Three sequences were chosen as aptamer candidates through sequencing and analysis and were transformed into fluorescent probes to evaluate their interactions with thiamethoxam. A fluorescent turn-on aptasensor for thiamethoxam based on the best aptamer (FAM-Thi13) and a short quenching strand were further designed and showed a quantitative linear range from 10 to 1000 nM with a detection limit of 1.23 nM for thiamethoxam. Molecular docking and molecular dynamics were used to investigate the binding site of the main probe of the aptasensor (FAM-Thi13) and thiamethoxam. Satisfactory results were also obtained in quantifying thiamethoxam in environmental water samples by the developed fluorescent aptasensor.

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