Fiber-optic immunosensor for mycotoxins.

Area of Science:

• Analytical Chemistry
• Biosensing Technology
• Food Safety

Background:

• Mycotoxin contamination, particularly fumonisins and aflatoxins, poses a significant threat to maize quality and human health.
• Accurate and rapid detection methods are crucial for ensuring food safety and agricultural trade.
• Fiber-optic immunosensors offer a promising platform for sensitive and selective toxin detection.

Purpose of the Study:

• To develop and evaluate evanescent wave-based fiber-optic immunosensors for detecting fumonisin B1 (FB1) and aflatoxin B1 (AFB1) in maize.
• To compare the performance of competitive and non-competitive assay formats.
• To assess the impact of sample pre-treatment methods on sensor sensitivity and accuracy.

Main Methods:

• Development of competitive fiber-optic immunosensors for FB1 using monoclonal antibodies and fluorescence labeling.
• Development of a non-competitive fluorescence-based sensor for AFB1 detection.
• Evaluation of different maize sample clean-up procedures (dilution vs. affinity column).
• Comparison of immunosensor results with High-Performance Liquid Chromatography (HPLC) for FB1 detection.

Main Results:

• The competitive FB1 immunosensor showed an inverse relationship between signal and toxin concentration.
• Affinity column clean-up improved FB1 detection limits by tenfold compared to simple dilution.
• The non-competitive AFB1 sensor detected toxins directly via native fluorescence, with a limit of detection of 2 ng/mL.
• Immunosensor and HPLC methods showed good agreement for FB1, with discrepancies arising from cross-reactive fumonisins.

Conclusions:

• Evanescent wave fiber-optic sensors demonstrate potential for rapid screening of mycotoxins in maize.
• Effective sample clean-up is essential for optimizing the performance of these immunosensors.
• Further development may lead to robust tools for real-time food safety monitoring.