posted on 2020-03-16, 20:29authored bySandra Leonardo, Greta Gaiani, Takeshi Tsumuraya, Masahiro Hirama, Jean Turquet, Núria Sagristà, Maria Rambla-Alegre, Cintia Flores, Josep Caixach, Jorge Diogène, Ciara K. O’Sullivan, Carles Alcaraz, Mònica Campàs
The
importance of ciguatoxins (CTXs) in seafood safety and their
emerging occurrence in locations far away from tropical areas highlight
the need for simple and low-cost methods for the sensitive and rapid
detection of these potent marine toxins to protect seafood consumers.
Herein, an electrochemical immunosensor for the detection of CTXs
is presented. A sandwich configuration is proposed, using magnetic
beads (MBs) as immobilization supports for two capture antibodies,
with their combination facilitating the detection of CTX1B, CTX3C,
54-deoxyCTX1B, and 51-hydroxyCTX3C. PolyHRP-streptavidin is used for
the detection of the biotinylated detector antibody. Experimental
conditions are first optimized using colorimetry, and these conditions
are subsequently used for electrochemical detection on electrode arrays.
Limits of detection at the pg/mL level are achieved for CTX1B and
51-hydroxyCTX3C. The applicability of the immunosensor to the analysis
of fish samples is demonstrated, attaining detection of CTX1B at contents
as low as 0.01 μg/kg and providing results in correlation with
those obtained using mouse bioassay (MBA) and cell-based assay (CBA),
and confirmed by liquid chromatography coupled to high-resolution
mass spectrometry (LC-ESI-HRMS). This user-friendly bioanalytical
tool for the rapid detection of CTXs can be used to mitigate ciguatera
risk and contribute to the protection of consumer health.