Abstract
Ochratoxin A (OTA) is one of the most common mycotoxins contaminating feed and foodstuffs. Therefore, a great deal of concern is associated with AFB1 toxicity. In this work, a fast and sensitive fluorescence aptamer biosensor has been proposed for the OTA assay. In the absence of OTA, the OTA aptamer can form a G-quadruplex structure with thioflavin T (ThT) dye, which results in increased fluorescence. After joining OTA, OTA aptamer combines with OTA and the G-quadruplex can be formed. Only faint fluorescence was finally observed when ThT weakly reacts with the quadruplex. Through this test method, the entire reaction and analysis process of OTA can be completed in 10 min. Under optimal experimental conditions (600 nM OTA-APT, 7 μM ThT, and 3 min incubation time), this proposed assay has a good limit of detection (LOD) of 0.4 ng/mL and shows a good linear relationship within the range of 1.2–200 ng/mL under the best experimental conditions. This method has a high specificity for OTA relative to Ochratoxin B (23%) and Aflatoxin B1 (13%). In addition, the quantitative determination of this method in real samples has been validated using a sample of red wine supplemented with a range of OTA concentrations (1.2 ng/mL, 12 ng/mL, and 40 ng/mL) with recoveries of 96.5% to 107%.
Highlights
This method has a high specificity for Ochratoxin A (OTA) relative to Ochratoxin B (23%) and Aflatoxin B1 (13%)
Ochratoxin A (OTA) is a well-known mycotoxin produced by various Aspergillus and Penicillium strains and found in many foods such as cereals, coffee, cocoa, dried fruit, wine and grape juice, beer, spices, meat, and meat products [1,2,3,4,5,6]
After joining OTA, the OTA aptamer combines with OTA and forms the antiparallel antiparallel G-quadruplex
Summary
Ochratoxin A (OTA) is a well-known mycotoxin produced by various Aspergillus and Penicillium strains and found in many foods such as cereals, coffee, cocoa, dried fruit, wine and grape juice, beer, spices, meat, and meat products [1,2,3,4,5,6]. Chen et al developed a simple and rapid biosensor for OTA based on a structure-switching signaling aptamer [19]. A series based methods for detecting OTA has been reported. These assays mainly include fluorescence of aptamer-based methods for detecting OTA has been reported These assays mainly include [27,28], electrochemical assays [29,30], colorimetric analysis [31,32,33], nanomaterials [34,35], and fluorescence [27,28], electrochemical assays [29,30], colorimetric analysis [31,32,33], nanomaterials [34,35], photoelectrochemical immunosensors [36].
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