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An Electrochemical Sensor Based on Structure Switching of Dithiol-modified Aptamer for Simple Detection of Ochratoxin
Donny Nugraha Mazaafrianto1, Akihiko Ishida2, Masatoshi Maeki2
1Graduate School of Chemical Sciences and Engineering, Hokkaido University.
Abstract:
In this study, we developed an electrochemical sensor for ochratoxin A (OTA) by using an aptamer having a dithiol-based anchor, which exhibited higher stability on a gold electrode than a monothiol-based aptamer because of its two anchors. The sensor was also based on a signal-on scheme that produces a signal current resulting from structure-switching of the aptamer upon interaction with OTA. For simple fabrication of this sensor, the non-covalent interaction of methylene blue with the aptamer was also employed as an electrochemical indicator. In this study, the performance of the sensor, including the dissociation constant of the aptamer-OTA complex, was characterized. The proposed sensor exhibited high reproducibility and enough sensitivity to detect the minimum amount of OTA required for the analysis of real food samples with a limit of detection of 113 pM.
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