A novel impedimetric aptasensor based on AuNPs–carboxylic porous carbon for the ultrasensitive detection of ochratoxin A

Abstract

A novel aptasensor based on AuNPs-carboxylic porous carbon (cPC) is developed for the ultrasensitive detection of ochratoxin A (OTA) via electrochemical impedance spectroscopy. The prepared AuNPscPC, which combines the porous structure of cPC with the good conductivity of AuNPs, is used as an excellent carrier for the immobilization of capture DNA (cDNA), which enhances the loading of the aptamer and amplifies the impedimetric signal. When the target OTA is present, due to the complex effect of the three-dimensional macroporous structure of the AuNPs-cPC on the immobilization of cDNA, hybridization between the aptamer and cDNA and the conformational change of the OTAaptamer, the OTA-aptamer complex may not be released from the electrode surface, which leads to an increase in the R ct signal. Through optimization of the important parameters, the optimal aptamer concentration of 10 mmol L À1 and optimal incubation time of 9 min are obtained. Under the optimal conditions, the DR ct is linearly proportional to OTA concentration in a logarithmic way in the range of 1 Â 10 À8 to 0.1 ng mL À1, and the actual limit of detection is 1 Â 10 À8 ng mL À1.

Label-Free and Highly-Sensitive Detection of Ochratoxin A Using One-Pot Synthesized Reduced Graphene Oxide/Gold Nanoparticles-Based Impedimetric Aptasensor

“…Furthermore, the occurrence of aptamers as the remarkable recognition probes with high specificity and affinity, fast response, simple operation, low cost, and miniaturization, have been used as convenient, sensitive, and robust methods for OTA monitoring with the necessary help of advanced nanomaterials in foodstuffs [ 8 , 9 ]. The electrochemical aptasensors are classified into label-free and label-based types relying on whether the detection signals are from redox-labelled aptamers [ 10 ] or the redox probe in the electrolyte [ 11 ]. The redox-labelled aptamer EC sensor exhibits high sensitivity; however, the complex construction and high cost limited its development [ 12 ].…”

Electrochemical Aptasensor for Zearalenone Based on DNA Assembly and Exonuclease III as Amplification Strategy

“…To improve the electrochemical performance, researchers have introduced different nanomaterials with good conductivity and catalytic activity on the electrode surface for signal amplification [14, 15]. However, the preparation and modification of nanomaterials are complicated and unstable.…”

A Non-Enzyme and Non-Label Sensitive Fluorescent Aptasensor Based on Simulation-Assisted and Target-Triggered Hairpin Probe Self-Assembly for Ochratoxin a Detection

“…Since the OTA aptamer has been reported [ 23 ], a great deal of aptamer-based biosensors for detecting OTA have been widely developed. Besides, many signal amplification techniques have also been reported to improve the sensitivity and dynamic detection range, including colorimetric and optical determination based on nanoparticles [ 24 , 25 ], nicking enzyme-assisted fluorescence signal enhancement [ 26 , 27 ], electrochemical impedance spectroscopy based on gold nanoparticles [ 28 , 29 ], fluorescence determination based on dye labeling [ 30 ], etc. These methods can greatly reduce the detection limit of the biosensors, but unfortunately, the use of nanomaterials can be disturbed by other electroactive substances coexisting in actual samples [ 31 ].…”