title: Aptamer contained triple-helix molecular switch for rapid fluorescent sensing of acetamiprid.
abstract: In this study, an aptamer-based fluorescent sensing platform using triple-helix molecular switch (THMS) was developed for the pesticide screening represented by acetamiprid. The THMS was composed of two tailored DNA probes: a label-free central target specific aptamer sequence flanked by two arm segments acting as a recognition probe; a hairpin-shaped structure oligonucleotide serving as a signal transduction probe (STP), labeled with a fluorophore and a quencher at the 3' and 5'-end, respectively. In the absence of acetamiprid, complementary bindings of two arm segments of the aptamers with the loop sequence of STP enforce the formation of THMS with the "open" configuration of STP, and the fluorescence of THMS is on. In the presence of target acetamiprid, the aptamer-target binding results in the formation of a structured aptamer/target complex, which disassembles the THMS and releases the STP. The free STP is folded to a stem loop structure, and the fluorescence is quenched. The quenched fluorescence intensity was proportional to the concentration of acetamiprid in the range from 100 to 1200nM, with the limit of detection (LOD) as low as 9.12nM. In addition, this THMS-based method has been successfully used to test and quantify acetamiprid in Chinese cabbage with satisfactory recoveries, and the results were in full agreement with those from LC-MS. The aptamer-based THMS presents distinct advantages, including high stability, remarkable sensitivity, and preservation of the affinity and specificity of the original aptamer. Most importantly, this strategy is convenient and generalizable by virtue of altering the aptamer sequence without changing the triple-helix structure. So, it is expected that this aptamer-based fluorescent assay could be extensively applied in the field of food safety inspection.
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Xin
authors: X
authors: Liu
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Ying
authors: Y
authors: Li
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Jing
authors: J
authors: Liang
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Wenyue
authors: W
authors: Zhu
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Jingyue
authors: J
authors: Xu
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Ruifang
authors: R
authors: Su
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China.
authors: Lei
authors: L
authors: Yuan
authors: Department of Food Quality and Safety, College of Food Science and Engineering, Jilin University, Changchun 130062, China. Electronic address: sunchuny@jlu.edu.cn.
authors: Chunyan
authors: C
authors: Sun
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D001937:Brassica / Q000737:chemistry; D005453:Fluorescence; D005506:Food Contamination / Q000032:analysis; D007306:Insecticides / Q000032:analysis* / Q000737:chemistry; D000073943:Neonicotinoids / Q000032:analysis* / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D052157:Aptamers, Nucleotide; D007306:Insecticides; D000073943:Neonicotinoids; C464485:acetamiprid
keywords: Acetamiprid; Aptamer; Fluorescence; Triple-helix molecular switch