CRISPR/Cas12a-Derived Photoelectrochemical Aptasensor
Based on Au Nanoparticle-Attached CdS/UiO-66-NH2 Heterostructures
for the Rapid and Sensitive Detection of Ochratoxin A
posted on 2023-12-29, 12:04authored byXiaobo Zhang, Zhiru Li, Lili Yang, Bing Hu, Qiuyue Zheng, Jiang Man, Jijuan Cao
The sensitive and accurate detection
of ochratoxin A (OTA) is crucial
for public health due to its high toxicity. Herein, using Au nanoparticle
(NP)-attached CdS/UiO-66-NH2 heterostructures as photoactive
materials, a photoelectrochemical (PEC) aptasensor was presented for
the ultrasensitive assay of OTA based on a competitive displacement
reaction triggering the trans-cleavage ability of CRISPR/Cas12a. In
this sensing strategy, methylene blue-labeled single-stranded DNA
(MB-ssDNA) was immobilized on the Au NPs/CdS/UiO-66-NH2 electrode to accelerate the separation of the photogenerated carrier,
thus producing a significantly increased PEC response. In the presence
of OTA, it specifically bound with the aptamer (Apt) and resulted
in the release of the activation chain, triggering the trans-cleavage
characteristics of CRISPR/Cas12a. MB-ssDNA was cut randomly on the
electrode surface to convert the PEC signal from the “on”
to the “off” state, thereby achieving a quantitative
and accurate detection of OTA. The CRISPR/Cas12a-derived PEC aptasensor
exhibited excellent sensitivity and specificity, with a linear range
from 100 to 50 ng/mL and a detection limit of 38 fg/mL. Overall, the
proposed aptasensor could provide a rapid, accurate, and sensitive
method for the determination of OTA in actual samples.