Development of enzyme-linked immunosorbent assay with nanogold-labeled probes for detection of diarrhetic shellfish toxins.

Diarrheal shellfish toxins (DSTs) are a type of liposoluble toxins produced by toxic algae in the ocean, with main components of okadaic acid (OA), dinotricin-1 (DTX-1), and dinotricin-2 (DTX-2). They can accumulate in shellfish through food chain. Human consumption of toxic shellfish can have adverse effects on health. Therefore, conducting DSTS detection can effectively ensure food safety. Base on the principle of competitive enzyme-linked immunosorbent assay (ELISA), referring to the seed growth method, we prepared goldnano rods using gold nanoparticles (AuNPs), and conjugated them with okadaic acid antibody-horseradish peroxidase (OA-HRP) to form nanoprobes, which together established a novel ELISA technology of goldnano rods labeled OA-HRP. The technology presented significant detection advantages with a detection limit of 2.32 ng·mL-1, a quantification limit of 2.97 ng·mL-1, and a sample recovery rate of 85.2% to 117.8%. Both the intra-batch and inter-batch varia-tion coefficients were below 20.0%. The proposed method demonstrated high specificity for okadaic acid (OA), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2), with no cross-reactions observed against six other lipophilic toxins-azaspiracid-1, azaspiracid-2, and azaspiracid-3 (AZA-1, AZA-2, AZA-3), pectenotoxin-2 (PTX-2), yessotoxin (YTX), and homo-yessotoxin (hYTX). Moreover, it showed good correlation with the determination results of liquid chromatography-tandem mass spectrometry (LC-MS/MS). The goldnano rods labeled OA-HRP direct ELISA method established here significantly improved the detection sensitivity of DSTs, which could be used for rapid quantitative detection and analysis of DSTs in seafood, with significant application prospects.