A competitive fluorescence assay based on free-complementary DNA for ochratoxin A detection

Area of Science:

• Analytical Chemistry
• Biotechnology
• Food Safety

Background:

• Ochratoxin A (OTA) is a common food contaminant with significant health implications.
• Accurate and sensitive detection methods for OTA are crucial for food safety and regulatory compliance.

Purpose of the Study:

• To develop an ultrasensitive, rapid, and specific method for Ochratoxin A (OTA) detection.
• To utilize molecular beacons (MBs) with aptamer-based probes for enhanced OTA sensing.

Main Methods:

• Designed a molecular beacon (MB) with a loop structure mimicking an aptamer sequence.
• Employed complementary DNA (cDNA) to translate OTA presence into a measurable fluorescence response.
• Optimized assay conditions for fluorescence intensity measurement and detection limit.

Main Results:

• Achieved a linear correlation between fluorescence intensity and OTA concentration from 10 pg/mL to 1 µg/mL.
• Established a highly sensitive detection limit of 0.247 pg/mL for OTA.
• Validated the assay's performance in wheat samples, showing comparable results to HPLC-MS/MS.

Conclusions:

• The developed aptamer-based MB assay is a sensitive and specific platform for OTA detection.
• This method demonstrates potential as a viable alternative to conventional techniques like HPLC-MS/MS for routine OTA analysis.
• The assay offers a rapid and efficient approach for monitoring OTA contamination in food products.