Homogeneous Electrochemical Method for Ochratoxin A Determination Based on Target Triggered Aptamer Hairpin Switch and Exonuclease III-Assisted Recycling Amplification
A simple, fast, sensitive, and homogeneous electrochemical method has been developed for ochratoxin A (OTA) determination, which combines the advantage of the high selectivity of aptamer to OTA and high efficiency of exonuclease (Exo) III-assisted recycling amplification mechanism. The metastable hairpin probe (HP) was designed into three parts: regions I is the aptamer of OTA as the target recognition; regions II is poly[dA] sequence as extended DNA (E-DNA); regions III as the target DNA (T-DNA) is complementary to a part of the aptamer to stabilize the hairpin-sharp form of the HP in the absence of OTA. The DNA probe with a methylene blue tag at its 3′ terminus (MB-DNA) was designed to be complementary with T-DNA. Introduction of OTA into the assay leads to the formation change of HP from hairpin shape to open form, thus facilitating the hybridization between T-DNA and MB-DNA. The electrochemical signal is amplified through continuous Exo III cleavage. Under the optimal conditions, the differential pulse voltammetric (DPV) response had a linear relationship with the logarithm of OTA concentration in the range of 0.001~0.5 ng mL−1. In addition, the developed method has been successfully applied to detect OTA in wheat standard quality control sample. This homogeneous electrochemical sensor may have a potential prospect in detecting other molecules or proteins, which possesses the corresponding aptamer, through easily designing the hairpin probe.
KeywordsHomogeneous electrochemical detection Ochratoxin A Recycling amplification
This work was supported by the Scientific Research Foundation for Returned Scholars, Ministry of Education of China (No. LXKQ201301), Fujian Spark Program (No. 2016S0042), Science and Technology Program of Fujian, China (No. 2016 N0017), Natural Science Foundation of China (No. 31571779), High and New project of Fujian Marine Fisheries Department (No. 20), Fujian Production and Study project of Provincial Science and Technology Hall (No. 2016 N5006), China.
Compliance with Ethical Standards
Conflict of Interest
Chang Liu declares that she has no conflict of interest. Yajing Guo declares that she has no conflict of interest. Fang Luo declares that she has no conflict of interest. Pingfan Rao declares that he has no conflict of interest. Caili Fu declares that he has no conflict of interest. Shaoyun Wang declares that she has no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
Informed consent is not applicable in this study.
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