An amperometric sensor coupled to a haemolytic-enzymatic assay for the detection of palytoxin in clams

Palytoxin (PlTX) is a potent marine toxin produced by dinoflagellates of the genus Ostreopsis now distributed worldwide, also in the Mediterranean Sea, posing serious risks to human health. In fact, occurrence of Ostreopsis... [ view full abstract ]

Palytoxin (PlTX) is a potent marine toxin produced by dinoflagellates of the genus Ostreopsis now distributed worldwide, also in the Mediterranean Sea, posing serious risks to human health. In fact, occurrence of Ostreopsis spp may result in PlTX contamination of seafood or may cause intoxication by aerosol exposure. At the moment no regulation or limits are established for PlTX and its analogues (PlTXs) in seafood. Considering the high toxicity of the PlTX, in order to protect the human health, EFSA requires to develop rapid and sensitive detection methods.

We developed an amperometric sensor for PlTX detection, based on the measurement of lactic dehydrogenase (LDH) released after haemolysis of sheep erythrocytes caused by PlTX.

The aim of this study was to assess the applicability of our method for PlTX detection in clams.

A simple and rapid extraction procedure has provided the best results in terms of both efficiency and matrix interference on palytoxin detection. This extraction procedure, evaluated by using standard solutions of PlTX and experimentally contaminated clams, includes: blending of 10 g of whole clam tissue with 90 ml of 60% Methanol, centrifugation, shaking with Dichloromethane (1:1 v/v), collection of the aqueous phase and, finally, a dilution 1:50 in Phosphate Buffer Saline (PBS).

Preliminary results about the applicability of the sensor to clams samples have been obtained by analyzing 10 samples from Vietnam.

The method, rapid, specific, sensitive and cost-effective, could be an useful tool to detect PlTX in clams.