Structure-switching fluorescence aptasensor for sensitive detection of chloramphenicol
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ORIGINAL PAPER
Structure-switching fluorescence aptasensor for sensitive detection of chloramphenicol Pengfei Ma 1,2,3 & Yuhan Sun 1,2,3 & Imran Mahmood Khan 1,2,3 & QianHui Gu 1,2,3,4 & Lin Yue 1,2,3 & Zhouping Wang 1,2,3,5,6 Received: 2 May 2020 / Accepted: 2 August 2020 # Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract The performance of chloramphenicol aptamer, including binding thermodynamics, structure switching, and binding domain, was investigated by isothermal titration calorimetry, circular dichroism, and molecular docking. Then, a new fluorescence aptasensor was developed with signal amplification mediated by exonuclease I-catalyzed reaction and hybridization chain reaction (HCR) for chloramphenicol detection. In this system, the aptamer-binding domain is blocked by the initiator of HCR, the aptamer undergoes structure switching in the presence of chloramphenicol, and DNA dissociation occurs. The released aptamer is subsequently recognized and cleaved by Exo I to set free chloramphenicol. With the Exo I-assisted chloramphenicol recycling, an increasing number of initiators were exposed from the digestion of the initiator-aptamer complex. Then, the chain-like assembly of FAM labeled H1 and H2 through HCR was triggered by the initiator, generating a long DNA polymer. Under optimum conditions, the aptasensor exhibited a log-linear range from 0.001 to 100 nM of chloramphenicol and a detection limit of 0.3 pM. Additionally, the designed biosensing platform was applied to determine chloramphenicol in milk and lake water with high accuracy. The current approach provides a new avenue to develop sensitive aptasensors with the assistance of binding mechanism between aptamer and target compounds. Keywords Chloramphenicol . Binding mechanism . Aptasensor . Exonuclease I . Hybridization chain reaction
Introduction As a broad-spectrum antibiotic, chloramphenicol (CAP) has been widely used in aquatic products and poultry as the Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00604-020-04471-9) contains supplementary material, which is available to authorized users. * Zhouping Wang [email protected]; [email protected] 1
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
2
School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
3
International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
4
Three Squirrel Co., LTD, Wuhu 241000, China
5
Collaborative Innovation Center of Food Safety and Quality Control of Jiangsu Province, Jiangnan University, Wuxi 214122, China
6
School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116024, China
treatment of diseases and the growth promoters [1–3]. However, many previous studies have shown that the CAP residues exist in fish, pork, and shrimp which are closely associated with the occurrence of human diseases such as gray baby syndrome, apl
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