Aptamer-based fluorometric determination of Salmonella Typhimurium using Fe3O4 magnetic separation and CdTe quantum dots.

Autor: Junan Ren, Gang Liang, Yan Man, An Li, Xinxin Jin, Qingju Liu, Ligang Pan
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: PLoS ONE, Vol 14, Iss 6, p e0218325 (2019)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0218325
Popis: Based on the high sensitivity and stable fluorescence of CdTe quantum dots (QDs) in conjunction with a specific DNA aptamer, the authors describe an aptamer-based fluorescence assay for the determination of Salmonella Typhimurium. The fluorescence detection and quantification of S. Typhimurium is based on a magnetic separation system, a combination of aptamer-coated Fe3O4 magnetic particles (Apt-MNPs) and QD-labeled ssDNA2 (complementary strand of the aptamer). Apt-MNPs are employed for the specific capture of S. Typhimurium. CdTe QD-labeled ssDNA2 was used as a signaling probe. Simply, the as-prepared CdTe QD-labeled ssDNA2 was first incubated with the Apt-MNPs to form the aptamer-ssDNA2 duplex. After the addition of S. Typhimurium, they could specifically bind the DNA aptamer, leading to cleavage of the aptamer-ssDNA2 duplex, accompanied by the release of CdTe QD-labeled DNA. Thus, an increased fluorescence signal can be achieved after magnetic removal of the Apt-MNPs. The fluorescence of CdTe QDs (λexc/em = 327/612 nm) increases linearly in the concentration range of 10 to 1010 cfu•mL-1, and the limit of detection is determined to be 1 cfu•mL-1. The detection process can be performed within 2 h and is successfully applied to the analysis of spiked food samples with good recoveries from 90% to 105%.
Databáze: Directory of Open Access Journals
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