Highly sensitive colorimetric aptasensor for ochratoxin A detection based on enzyme-encapsulated liposome

Area of Science:

• Biosensing
• Analytical Chemistry
• Food Safety

Background:

• Ochratoxin A (OTA) is a prevalent mycotoxin posing significant health risks.
• Accurate and sensitive detection methods for OTA are crucial for food safety.
• Existing detection methods can be complex and costly.

Purpose of the Study:

• To develop a simple, low-cost, and sensitive colorimetric aptasensor for OTA detection.
• To utilize liposomes and magnetic beads for enhanced detection capabilities.
• To validate the aptasensor's performance in real food samples.

Main Methods:

• Design of a dumbbell-shaped probe with magnetic beads, dsDNA, and enzyme-encapsulated liposomes.
• Utilizing OTA aptamer's specific binding to form G-quadruplex structures in the presence of OTA.
• Colorimetric detection based on HRP-catalyzed TMB oxidation, leading to a visible color change.

Main Results:

• The aptasensor demonstrated a sensitive response to OTA, with detection ranging from 0.05 to 2.0 ng/mL.
• A low limit of detection (LOD) of 0.023 ng/mL was achieved (S/N = 3).
• The method showed satisfactory performance when applied to OTA detection in corn samples.

Conclusions:

• A novel, highly sensitive, and cost-effective liposome-based colorimetric aptasensor for OTA detection has been successfully developed.
• The aptasensor offers a simple visual readout and potential for on-site food safety monitoring.
• This method provides a promising tool for the routine analysis of OTA in agricultural products.