Dr. O’Sullivan has published in collaboration with Sandra Leonardo, Greta Gaiani, Takeshi Tsumuraya, Masahiro Hirama, Jean Turquet, Nu?ria Sagrista?,Maria Rambla-Alegre, Cintia Flores, Josep Caixach, Jorge Dioge?ne, Carles Alcaraz,and Mo?nica Campa?s the following article:

Addressing the Analytical Challenges for the Detection ofCiguatoxins Using an Electrochemical Biosensor

Anal. Chem. 2020, 92, 4858?4865

Abstract:
The importance of ciguatoxins (CTXs) in seafood safety andtheir emerging occurrence in locations far away from tropical areas highlightthe need for simple and low-cost methods for the sensitive and rapiddetection of these potent marine toxins to protect seafood consumers.Herein, an electrochemical immunosensor for the detection of CTXs ispresented. A sandwich configuration is proposed, using magnetic beads(MBs) as immobilization supports for two capture antibodies, with theircombination facilitating the detection of CTX1B, CTX3C, 54-deoxyCTX1B,and 51-hydroxyCTX3C. PolyHRP-streptavidin is used for the detection ofthe biotinylated detector antibody. Experimental conditions arefirstoptimized using colorimetry, and these conditions are subsequently usedfor electrochemical detection on electrode arrays. Limits of detection at thepg/mL level are achieved for CTX1B and 51-hydroxyCTX3C. Theapplicability of the immunosensor to the analysis offish samples is demonstrated, attaining detection of CTX1B at contents aslow as 0.01?g/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-friendlybioanalytical tool for the rapid detection of CTXs can be used to mitigate ciguatera risk and contribute to the protection of consumer health.