A Simple Structure-Switch Aptasensor Using Label-Free Aptamer for Fluorescence Detection of Aflatoxin B1

Area of Science:

• Biochemistry
• Analytical Chemistry
• Food Science

Background:

• Aflatoxin B1 (AFB1) is a toxic mycotoxin contaminating food, posing significant health risks.
• Sensitive detection methods for AFB1 are crucial for food safety and quality control.
• Aptamers offer high specificity and affinity for target molecules, making them suitable for biosensor development.

Purpose of the Study:

• To develop a simple and sensitive aptamer-based fluorescence assay for detecting AFB1.
• To utilize a structure-switching mechanism for label-free AFB1 detection.
• To validate the assay's performance in complex food matrices.

Main Methods:

• Aptamer structure-switch assay utilizing a label-free aptamer, a fluorescein (FAM)-labeled complementary strand (FDNA), and a quencher (BHQ1)-labeled complementary strand (QDNA).
• Fluorescence detection based on the conformational change of the aptamer upon binding to AFB1, altering the proximity of FAM and BHQ1.
• Assay validation using standard solutions and spiked food samples (beer, corn flour).

Main Results:

• The assay demonstrated a low detection limit of 61 pM AFB1.
• A wide dynamic concentration range of 61 pM to 4 μM was achieved.
• The method successfully detected AFB1 in complex sample matrices like beer and corn flour.

Conclusions:

• The developed aptamer structure-switch assay provides a sensitive and specific method for AFB1 detection.
• This label-free fluorescence assay is suitable for rapid and reliable monitoring of AFB1 in food products.
• The method holds promise for improving food safety and quality control measures.