Abstract
Salmonella Typhimurium (S. Typhimurium) is a globally distributed foodborne pathogen, which can lead to outbreaks of foodborne infectious diseases. It is essential to guarantee food safety by timely and correct detection of S. Typhimurium. In this investigation, an original fluorescence aptasensor was constructed to detect S. Typhimurium rapidly and sensitively. Through the coupling of magnetic beads, aptamer, and gold nanoparticles (AuNPs), a fluorescence quenching system with a “sandwich structure” was established. The aptamer acted as a link, and its specific binding to S. Typhimurium could release AuNPs from the system. Meanwhile, fluorescent DNA-stabilized silver nanoclusters (DNA-AgNCs) were synthesized. The fluorescence intensity changes caused by the fluorescence resonance energy transfer between DNA-AgNCs and AuNPs were utilized to detect S. Typhimurium. The purposed aptasensor exhibited high selectivity and sensitivity with a linear response to S. Typhimurium, ranging from 3.7 × 102 to 3.7 × 105 cfu/mL. The limit of detection (LOD) was estimated to be 98 cfu/mL within 2 h 10 min. In addition, this method showed excellent application for detection of S. Typhimurium in artificially contaminated milk, with LOD reaching 3.4 × 102 cfu/mL. Therefore, the developed fluorescence aptasensor has great potential to identify S. Typhimurium in foodstuffs.
Highlights
Immunological assays based on antigen–antibody interaction include the structures of antibodies that are deformed under high temperature and batch-to-batch variation in functionality [5]
The establishment of the system was mainly based on the complementary hybridization between cDNA1 and the aptamer
DNA-AgNCs served as the fluorescence signal for this assay
Summary
Typhimurium is the consumption of contaminated eggs, vegetables, fruits, poultry, meat, and milk [2]. The presence of this organism in food poses a severe threat to public safety. Typhimurium, including traditional culture, molecular detection, and immunological detection. The traditional culture method is the most commonly used detection technique, but it is time-consuming and cost-intensive [3]. Several molecular detection methods, such as PCR and LAMP, require expensive instruments and complex DNA extraction procedures [4]. It is quite essential to set up a rapid, convenient, and accurate method of detection to ensure food safety, especially for the screening of specific recognition elements of S.
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