Regenerable immuno-biochip for screening ochratoxin A in green coffee extract using an automated microarray chip...

Area of Science:

• Food safety analysis
• Biosensor technology
• Mycotoxin detection

Background:

• Ochratoxin A (OTA) is a toxic food contaminant found at ppb to ppm levels.
• Effective removal of OTA from food is challenging.
• Rapid and sensitive detection methods are crucial for regulatory compliance and public health.

Purpose of the Study:

• To develop a rapid and efficient method for Ochratoxin A detection.
• To create a reusable biochip for Ochratoxin A analysis.
• To meet legal maximum residual limits for food contaminants.

Main Methods:

• Synthesis of an OTA conjugate functionalized with a water-soluble peptide.
• Covalent immobilization of the conjugate onto a glass biochip using contact spotting.
• Indirect competitive immunoassay with flow-through reagent addition.
• Chemiluminescence detection using the automated Munich Chip Reader 3 (MCR 3) platform.
• Analysis of buffer models and real green coffee extracts.

Main Results:

• The developed biochip enabled covalent conjugate immobilization.
• The biochip surface supported at least 20 assay-regeneration cycles.
• Total analysis time per sample was 12 minutes, including regeneration.
• The limit of quantification (LOQ) for OTA in green coffee extract was 0.3 μg L⁻¹, equivalent to 7 μg kg⁻¹.

Conclusions:

• The covalent immobilization strategy provides a robust and reusable biochip surface for OTA detection.
• The developed immunoassay offers a rapid and sensitive method for Ochratoxin A determination in food matrices.
• This method facilitates compliance with regulatory limits for food safety.