A non-enzymatic nanomagnetic electro-immunosensor for determination of Aflatoxin B1 as a model antigen

A nonenzymatic sandwich-type electrochemical immunosensor was developed by means of a modified glassy carbon electrode: GCE/chitosan/Au nanoparticle (AuNP)/anti-Aflatoxin B1 (a AFB1), and a Fe3O4 magnetic core with a gold shell functionalized with 3-((2-mercaptoethylimino)methyl)benzene-1,2-diol and labeled with an AFB1. The immunosensor was used for the detection of Aflatoxin B1 as a model antigen. The current originated from the conversion of catechol to o-quinone and vice versa within a quasi-reversible two electrons–two protons reaction, considered as the response. The electrochemical studies demonstrated that the proposed immunoelectrode can be used to detect AFB1 in the range of 0.6–110 ng mL−1 with a detection limit of 0.2 ng mL−1. This immunosensor can be simply regenerated by using an external magnetic field which ensures a reproducible response.