A bimetallic (Cu-Co) Prussian Blue analogue loaded with gold nanoparticles for impedimetric aptasensing of ochratoxin a
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Bimetallic (Cu-Co) Prussian Blue analogs (PBAs) were coupled to gold nanoparticles to give a nanocomposite of type AuNP@CuCoPBA. It is shown to be a viable material for the impedimetric aptamer-based determination of ochratoxin A (OTA). Basic characterizations revealed that the chemical composition and crystal structure of AuNP@CuCoPBA is similar to that of pristine CuCo PBA. Nevertheless, the nanocube shape of CoCu PBA is converted to small nanoparticles on addition of AuNPs. Compared with CuCoPBA-based aptasensor, the AuNP@CuCoPBA-based assay exhibits excellent electrochemical conductivity, strong aptamer binding interaction, and high G-quadruplex stability. Electrochemical impedance spectroscopy revealed that the assay has limits of detection as low as 5.2 fg mL−1 of OTA, a response in the 50 fg mL−1 to 10 ng mL−1 concentration range, high selectivity, good reproducibility, repeatability, and acceptable applicability. In our perception, it represents a universal and powerful method for aptamer strand immobilization. It may be applied to the determination of various other analytes for which aptamers are available.
KeywordsDetection of mycotoxins Electrochemical biosensor Metal-organic frameworks Nanocomposites Food safety testing
This work was supported by Programs for the National Natural Science Foundation of China, China (NSFC: Account Nos. 81601082, 81371363, and U1604127) and Innovative Technology Team of Henan Province, China (CXTD2014042).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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