DNA walker-assisted aptasensor for highly sensitive determination of Ochratoxin A

Area of Science:

• Analytical Chemistry
• Biosensors
• Nanotechnology

Background:

• Ochratoxin A (OTA) is a toxic fungal metabolite posing significant health risks to humans and animals.
• Accurate and sensitive detection methods for OTA are crucial for food safety and public health.
• Existing detection methods may lack sensitivity or require complex sample preparation.

Purpose of the Study:

• To develop a novel electrochemical aptasensor for the sensitive detection of Ochratoxin A (OTA).
• To utilize gold nanoparticles decorated molybdenum oxide (AuNPs-MoO_x) nanocomposites for enhanced performance.
• To integrate hybridization chain reaction (HCR) and a DNA walker machine for signal amplification.

Main Methods:

• Construction of an aptasensor using AuNPs-MoO_x nanocomposites.
• Implementation of HCR for embedding methylene blue (MB) signal molecules on silver nanoparticles (AgNPs).
• Employment of a restriction endonuclease (Nb.BbvCI)-aided DNA walker machine for signal amplification and detection via differential pulse voltammetry (DPV).

Main Results:

• The aptasensor demonstrated excellent analytical performance over a wide range (0.01-10000 pg mL^-1).
• Achieved a remarkably low detection limit of 3.3 fg mL^-1.
• The biosensor showed excellent agreement with ultraperformance liquid chromatography (UPLC) in analyzing real samples like juices, red wine, and serum.

Conclusions:

• The developed aptasensor provides a highly sensitive and reliable platform for OTA detection.
• The combination of AuNPs-MoO_x, HCR, and DNA walker machine offers effective signal amplification.
• This method holds promise for routine monitoring of OTA in food products and biological samples.