Ratiometric electrochemical aptasensor for ultrasensitive detection of Ochratoxin A based on a dual signal amplification strategy: engineering the binding of methylene blue to DNA

Zhu, Chengxi, Liu, Dong, Li, Yuye, Shen, Xiuli, Ma, Shuai, Liu, Yang, and You, Tianyan (2020) Ratiometric electrochemical aptasensor for ultrasensitive detection of Ochratoxin A based on a dual signal amplification strategy: engineering the binding of methylene blue to DNA. Biosensors and Bioelectronics, 150. 11814.

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Abstract

A novel ratiometric electrochemical aptasensor was developed for Ochratoxin A (OTA) detection based on the binding of methylene blue (MB) to DNA with a dual signal amplification strategy. The formation of dsDNA structures between ferrocene-labeled complementary DNA (Fc-cDNA), the OTA aptamer, and complementary helper DNA (hDNA) caused Fc away from the electrode, and allowed dsDNA to bind with a certain amount of MB. Here, a small oxidation current of Fc (IFc) and a large oxidation current of MB (IMB) were obtained. In the presence of OTA, its specific recognition with the aptamer induced the release of aptamer and hDNA from the electrode and subsequently the formation of hairpin structure for cDNA, which caused Fc close to the electrode and a weaker binding ability with MB. Then, an increased IFc and a decreased IMB were obtained. Based on this principle, OTA could be accurately quantified by measuring the ratiometric signal of IFc/IMB. Herein, the dual signal amplification strategy of the introduction of hDNA and the binding with MB after the OTA recognition was exploited to amplify the response signal. The obtained aptasensor showed a linear detection range from 10 pg mL1 to 10 ng mL1 and a detection limit of 3.3 pg mL1. The aptasensor was successfully applied to determine OTA in wheat, and the results were validated through HPLC-MS. Furthermore, by changing the target aptamers, this strategy could be universally used for the determination of various mycotoxins, showing prom-ising potential applications for mycotoxins monitoring in agricultural products and foods.

Item ID: 61270
Item Type: Article (Research - C1)
ISSN: 1873-4235
Keywords: electrochemical aptasensor; ratiometric strategy; Methylene blue; dual signal amplification; Ochratoxin A
Copyright Information: © 2019 Elsevier B.V. All rights reserved.
Funders: National Science Foundation of China (NSFC), National Science Foundation of Jiangsu Province (NSFJP), Innovation/Entrepreneurship Program of Jiangsu Province, Priority Academic Program Development of Jiangsu Higher Education Institutions, Postgraduate Research & Practice Innovation Program of Jiangsu Province
Projects and Grants: NSFC No. 21675065, NSFC No. 61901193, NSFJP No. BK20160490, PAPD-2018-87, KYCX19_1618
Date Deposited: 14 Jan 2020 23:57
FoR Codes: 03 CHEMICAL SCIENCES > 0301 Analytical Chemistry > 030102 Electroanalytical Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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