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Open AccessArticle

A Label-Free Fluorescent Aptasensor for Detection of Staphylococcal Enterotoxin A Based on Aptamer-Functionalized Silver Nanoclusters

1
School of Food Science and Technology, Shihezi University, Shihezi 832000, China
2
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
3
School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
4
Collaborative Innovation Center of Food Safety and Quality Control, Jiangnan University, Wuxi 214122, China
5
International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
*
Authors to whom correspondence should be addressed.
Polymers 2020, 12(1), 152; https://doi.org/10.3390/polym12010152
Received: 17 December 2019 / Revised: 2 January 2020 / Accepted: 6 January 2020 / Published: 7 January 2020
(This article belongs to the Section Polymer Applications)
Staphylococcal enterotoxin A (SEA) is a worldwide public health problem accounting for the majority of food poisoning which is produced by Staphylococcus aureus, threatening human health and leading to various foodborne diseases. Therefore, it is of great significance to develop a sensitive detection method for SEA to ensure food safety and prevent foodborne diseases in humans. In this study, an adaptive fluorescence biosensor for the detection of staphylococcal enterotoxin A (SEA) was designed and developed by combining DNA silver nanoclusters (DNA-AgNCs) with polypyrrole nanoparticles (PPyNPs). Fluorescent AgNCs, synthesized using aptamers as templates, were used as fluorescence probes, whose fluorescence was quenched by PPyNPs. In the presence of the target SEA, DNA-AgNCs were forced to desorb from the surface of PPyNPs through the binding of SEA with the aptamer-DNA-AgNCs, thereby resulting in fluorescence recovery. Under the optimized conditions, the relative fluorescence intensity (FI) showed a linear relationship with the SEA concentration in the range from 0.5 to 1000 ng/mL (Y = 1.4917X + 0.9100, R2 = 0.9948) with a limit of detection (LOD) of 0.3393 ng/mL. The sensor was successfully used to evaluate the content of SEA in milk samples, and the recovery efficiency of SEA was between 87.70% and 94.65%. Thus, the sensor shows great potential for application in food analysis. In short, the proposed platform consisted of an aptamer fluorescent sensor that can be used for the ultrasensitive detection of various toxins by taking advantage of the excellent affinity and specificity of corresponding aptamers. View Full-Text
Keywords: staphylococcal enterotoxin A (SEA); aptamer-functionalized AgNCs; polypyrrole nanoparticles (PPyNPs); fluorescence aptasensor detection staphylococcal enterotoxin A (SEA); aptamer-functionalized AgNCs; polypyrrole nanoparticles (PPyNPs); fluorescence aptasensor detection
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MDPI and ACS Style

Zhang, X.; Khan, I.M.; Ji, H.; Wang, Z.; Tian, H.; Cao, W.; Mi, W. A Label-Free Fluorescent Aptasensor for Detection of Staphylococcal Enterotoxin A Based on Aptamer-Functionalized Silver Nanoclusters. Polymers 2020, 12, 152.

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