Quantum Dot Nanobeads-Labelled Lateral Flow Immunoassay Strip for Rapid and Sensitive Detection of Salmonella Typhimurium Based on Strand Displacement Loop-Mediated Isothermal Amplification
Yuting Shang,
Shuzhen Cai,
Qinghua Ye,
Qingping Wu,
Yanna Shao,
Xiaoying Qu,
Xinran Xiang,
Baoqing Zhou,
Yu Ding,
Moutong Chen,
Liang Xue,
Honghui Zhu,
Jumei Zhang
Affiliations
Yuting Shang
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; State Key Laboratory of Food Science and Technology & National Engineering Research Center for Functional Foods & Synergetic Innovation Center of Food Safety & Joint International Research Laboratory on Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
Shuzhen Cai
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Qinghua Ye
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Qingping Wu
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Yanna Shao
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Xiaoying Qu
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Xinran Xiang
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Baoqing Zhou
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Yu Ding
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Moutong Chen
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Liang Xue
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Honghui Zhu
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
Jumei Zhang
Guangdong Provincial Key Laboratory of Microbial Safety and Health & State Key Laboratory of Applied Microbiology Southern China & Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Corresponding author.
Rapid, sensitive, point-of-care detection of pathogenic bacteria is important for food safety. In this study, we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip (QBs-labelled LFIAS) combined with strand displacement loop-mediated isothermal amplification (SD-LAMP) for quantitative Salmonella Typhimurium (ST) detection. Quantum dot nanobeads (QBs) served as fluorescence reporters, providing good detection efficiency. The customizable strand displacement (SD) probe was used in LAMP to improve the specificity of the method and prevent by-product capture. Detection was based on a sandwich immunoassay. A fluorescence strip reader measured the fluorescence intensity (FI) of the test (T) line and control (C) line. The linear detection range of the strip was 102–108 colony forming units (CFU)·mL−1. The visual limit of detection was 103 CFU·mL−1, indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips. ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction (PCR) and SD-LAMP. We detected ST in foods with an acceptable recovery of 85%–110%. The method is rapid, simple, almost equipment-free, and suitable for bacterial detection in foods and for clinical diagnosis.
