A dichromatic label-free aptasensor for sulfadimethoxine detection in fish and water based on AuNPs color and fluorescent dyeing of double-stranded DNA with SYBR Green I

•A dichromatic label-free aptasensor was established based on the higher affinity of SDM-aptamer to cDNA than that of SDM.•SDM can be quantitatively detected through both fluorescent emission and color changes of AuNPs.•The aptasensor can be applied to the rapid detection of SDM in fish and water sa...

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Bibliographic Details
Published in:Food chemistry 2020-03, Vol.309, p.125712-125712, Article 125712
Main Authors: Chen, Xiang-Xiu, Lin, Zheng-Zhong, Hong, Cheng-Yi, Yao, Qiu-Hong, Huang, Zhi-Yong
Format: Article
Language:English
Subjects:
Animals
Aptamers, Nucleotide - chemistry
Aptasensor
DNA - chemistry
Fish
Fishes - metabolism
Fluorescence
Fluorescent Dyes - chemistry
Gold - chemistry
Gold nanoparticles
Limit of Detection
Metal Nanoparticles - chemistry
Organic Chemicals - chemistry
Spectrometry, Fluorescence - methods
Sulfadimethoxine
Sulfadimethoxine - analysis
Water
Water - chemistry
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Summary:•A dichromatic label-free aptasensor was established based on the higher affinity of SDM-aptamer to cDNA than that of SDM.•SDM can be quantitatively detected through both fluorescent emission and color changes of AuNPs.•The aptasensor can be applied to the rapid detection of SDM in fish and water samples with high accuracy and sensitivity. A dichromatic label-free aptasensor was described for sulfadimethoxine (SDM) detection. Compared with the binding of SDM-aptamer to SDM, the higher affinity of aptamer to cDNA may result in the hybridization of dsDNA. In the presence of SDM, the aptamer specifically binds to SDM, leading to a blue color of AuNPs in deposit and fluorescence at 530 nm in supernatant after adding cDNA and SGI. With no target of SDM, AuNPs protected with the aptamer re-disperse in PBS with a red color, and no fluorescence occurs in supernatant. Based on the principle, SDM can be quantitatively detected through both fluorescent emission and AuNPs color changes with recoveries ranging from 99.2% to 102.0% for fish and from 99.5% to 100.5% for water samples. An analytical linear range of 2–300 ng mL−1 was achieved with the detection limits of 3.41 ng mL−1 for water and 4.41 ng g−1 for fish samples (3σ, n = 9).
ISSN:0308-8146
1873-7072
DOI:10.1016/j.foodchem.2019.125712