Immunorecognition magnetic supports for the development of an electrochemical immunoassay for azaspiracid detection in mussels

• Published in: Biosensors & bioelectronics 2017-06, Vol.92, p.200-206
• Main Authors: Leonardo, Sandra, Rambla-Alegre, Maria, Samdal, Ingunn A., Miles, Christopher O., Kilcoyne, Jane, Diogène, Jorge, O'Sullivan, Ciara K., Campàs, Mònica
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Immobilized - chemistry; Azaspiracid; Biosensing Techniques - methods; Bivalvia - chemistry; Electrochemical; Electrochemical Techniques - methods; Food Contamination - analysis; Horseradish peroxidase; Immunoassay; Immunoassay - methods; Limit of Detection; Magnetic bead; Marine Toxins - analysis; Mussel; Seafood - analysis; Spiro Compounds - analysis
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2017.02.015

As azaspiracids (AZAs) are being reported from the coastal waters of an increasing number of countries on a global scale, the need for rapid, simple and cost-effective methods to detect these marine toxins and protect seafood consumers’ health is becoming evident. A magnetic bead (MB)-based direct immunoassay for the detection of AZAs, using protein G-coated MBs as supports for antibody immobilisation and peroxidase-labelled AZA as a tracer is detailed. A colorimetric approach was first developed to optimise the experimental parameters and establish the cross-reactivity factors for AZA-1–10. The subsequent combination of the immunorecognition MBs with 8-electrode arrays enabled the multiplexed electrochemical detection of AZAs. Naturally-contaminated mussel samples were analysed and the results obtained showed an excellent correlation with LC-MS/MS analysis. The MB-based immunoassay facilitated the quantification of a wide range of AZA concentrations (120–2875μg AZA-1 equiv./kg), with a limit of detection (63μg AZA-1 equiv./kg) below the European regulatory threshold, using a protocol that requires very few steps and a short analysis time (~ 15min). The simplicity, cost-effectiveness, rapidity, robustness, selectivity and precision of the assay provide a valuable tool for the detection of all regulated AZAs and other toxic AZA analogues, suitable for end users in the field of food safety. •An electrochemical immunoassay for AZA detection is reported for the first time.•The immunoassay is based on the use of magnetic beads (MBs) as antibody supports.•The MB-based immunoassay detects all regulated AZAs and other AZA analogues.•Excellent correlation with LC-MS/MS is obtained in the analysis of mussel samples.•A user-friendly screening and quantification analysis tool for AZA is provided.