Magneto-controlled electrochemical immunoassay of brevetoxin B in seafood based on guanine-functionalized graphene nanoribbons

A facile and feasible magneto-controlled immunosensing platform was designed for sensitive electrochemical immunoassay of brevetoxin B (BTX-2) in seafood by using guanine-assembled graphene nanoribbons (GGNRs) as molecular tags on a home-made magnetic carbon paste electrode. Initially, monoclonal mouse anti-BTX-2 antibodies were covalently immobilized on the surface of magnetic beads, which were used as the immunosensing probes for the capture of BTX-2. The recognition elements were prepared by chemical modification of bovine serum albumin-BTX-2 conjugates (BTX-2-BSA) with the GGNRs. Based on a competitive-type immunoassay format, the formed magnetic immunocomplex was integrated on the electrode with an external magnet, followed by determination in pH 6.5 phosphate-buffered solution containing 2 μM Ru(bpy)3Cl2. Under optimal conditions, the electrochemical signals decreased with the increasing BTX-2 concentrations in the sample. The dynamic concentration range spanned from 1.0 pg mL−1 to 10 ng mL−1 with a detection limit of 1.0 pg mL−1 BTX-2. Inter- and intra-batch assay precisions were substantially improved by resorting to the GGNR manifold. The method featured unbiased identification of negative (blank) and positive samples. No significant differences at the 95% confidence level were encountered in the analysis of 12 spiked samples including S. constricta, M. senhousia and T. granosa between the electrochemical immunoassay and commercially available enzyme-linked immunosorbent assay (ELISA) for determination of BTX-2.

► We devise a magneto-controlled immunosensor for electrochemical detection of brevetoxin B.
► Antibody-functionalized magnetic beads as immunosensing probes.
► Biomolecules-functionalized graphene nanoribbons assembled guanine as molecular tags.
► Analysis of real samples and evaluation of method trueness.