Toehold-Mediated Cascade Catalytic Assembly for Mycotoxin Detection and Its Logic Applications

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Mycotoxins pose significant risks to food safety and human health.
• Current detection methods often lack sensitivity, selectivity, or require complex procedures.
• Development of rapid, sensitive, and specific biosensors is crucial for effective mycotoxin monitoring.

Purpose of the Study:

• To develop a novel enzyme-free biosensor for the ultrasensitive and selective detection of multiple mycotoxins.
• To utilize toehold-mediated catalytic hairpin assembly (CHA) and DNAzyme cascades for signal amplification.
• To demonstrate the application of this platform for mycotoxin quantification in real samples and for constructing logic gates.

Main Methods:

• An enzyme-free biosensor was designed using aptamer recognition, toehold-mediated catalytic hairpin assembly (CHA), and DNAzyme-cascaded hydrolysis.
• Mycotoxin binding releases a trigger DNA, initiating CHA to amplify the signal.
• Supramolecular nanostructures formed Mg2+-dependent DNAzymes that cleave a substrate, generating a measurable fluorescence signal.

Main Results:

• The biosensor achieved ultrasensitive detection limits: 0.2 pM for OTA, 0.13 pM for AFB1, and 0.17 pM for ZEN.
• High selectivity was observed, and the system was successfully applied to quantify mycotoxins in wine samples.
• The platform was utilized to create complex logic gates (AND-INHIBIT, INHIBIT-OR, OR-AND, OR-INHIBIT) for multiplexed mycotoxin detection.

Conclusions:

• The developed enzyme-free biosensor offers a highly sensitive, selective, and versatile platform for mycotoxin detection.
• The integration of CHA and DNAzyme cascades provides significant signal amplification.
• This technology holds great promise for intelligent food safety and environmental monitoring applications.