AUTHOR=Ni Xiao , Zhang Yuyan , Xue Chuhan , Chen Xiaojun 

TITLE=Ultrasensitive Detection of Ochratoxin A With a Zeolite Imidazolate Frameworks Composite–Based Electrochemical Aptasensor

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.858107

DOI=10.3389/fchem.2022.858107

ISSN=2296-2646

ABSTRACT=<p>Ochratoxin A (OTA) is a harmful mycotoxin, which is mainly secreted by <italic>Penicillium</italic> and <italic>Aspergillus</italic> species. In this work, an electrochemical aptasensor is presented for OTA detection based on Au nanoparticles (AuNPs) modified zeolite imidazolate frameworks (ZIFs) ZIF-8 platform and duplex-specific nuclease (DSN) triggered hybridization chain reaction (HCR) signal amplification. G-quadruplex-hemin assembled HCR nanowire acted as a nicotinamide adenine dinucleotide (NADH) oxidase and an HRP-mimicking DNAzyme. Besides, thionine (Thi) was enriched as a redox probe for signal amplification in this pseudobienzyme electrocatalytic system. Under the optimal conditions, the analytical response ranged from 1 to 10<sup>7</sup> fg ml<sup>−1</sup> with a detection limit of 0.247 fg ml<sup>−1</sup>. Furthermore, the aptasensor was proven to be applied in real wheat samples with a recovery between 96.8 and 104.2%, illustrating the potential prospects in practical detection.</p>