A fluorimetric method based on changes in membrane potential for screening paralytic shellfish toxins in mussels

Area of Science:

• Marine Biology
• Toxicology
• Analytical Chemistry

Background:

• Paralytic Shellfish Poisoning (PSP) poses a significant risk to public health.
• The current mouse bioassay for PSP toxins has limitations, necessitating alternative detection methods.
• Accurate monitoring of PSP toxins in seafood is crucial for consumer safety.

Purpose of the Study:

• To develop and validate a novel, sensitive assay for detecting PSP toxins.
• To provide a functional assay that estimates overall toxicity based on toxin potency.
• To establish a reliable screening method for PSP toxins in seafood and algae.

Main Methods:

• Development of a fluorimetric assay based on the functional activity of PSP toxins.
• Utilizing human excitable cells to detect changes in membrane potential caused by toxin binding to voltage-gated Na+ channels.
• Quantitation of toxins by measuring fluorescence, correlating signal intensity with toxic potency.

Main Results:

• The assay demonstrated high sensitivity with detection limits of 1 ng saxitoxin equivalents/ml.
• The method accurately estimates toxicity, as different PSP toxins bind to Na+ channels with varying affinities.
• The fluorescent assay proved specific, sensitive, rapid, and reliable for PSP toxin monitoring.

Conclusions:

• The developed fluorescent assay is a viable and effective alternative to the mouse bioassay for PSP toxin detection.
• This method offers a significant advancement in ensuring the safety of seafood products.
• The assay's sensitivity and reliability support its use in routine monitoring programs for toxic algae and contaminated shellfish.