A fluorescent aptasensor based on DNA-scaffolded silver-nanocluster for ochratoxin A detection

Area of Science:

• Analytical Chemistry
• Biotechnology
• Food Science

Background:

• Ochratoxin A (OTA) is a highly toxic and widespread mycotoxin, posing significant risks to food safety.
• Accurate and sensitive detection methods for OTA are crucial for regulatory compliance and public health protection.

Purpose of the Study:

• To develop a novel, highly sensitive, and specific signal-on fluorescent biosensor for the detection of ultratrace amounts of OTA.
• To demonstrate the feasibility of this biosensor for OTA detection in real food samples, specifically wheat.

Main Methods:

• Development of a fluorescent biosensor integrating DNA-scaffolded silver nanoclusters (AgNCs), structure-switching anti-OTA aptamer (Ap), and magnetic beads (MBs).
• Utilizing a signal-on fluorescence mechanism for enhanced detection sensitivity.
• Validation of the biosensor's performance using real wheat samples.

Main Results:

• The developed biosensor achieved a highly sensitive detection limit of 2 pg/mL for OTA.
• The method demonstrated high specificity in OTA detection.
• The biosensor exhibited superior fluorescence properties (quantum yield, photostability) compared to traditional methods.

Conclusions:

• This study presents the first application of DNA-scaffolded AgNCs for OTA detection, offering a promising alternative to existing methods.
• The biosensor combines the advantages of MBs and aptamers, providing ease of fabrication, convenience, low cost, and portability.
• The proposed sensor represents a significant advancement for routine ochratoxin A control in food safety applications.