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 B-1 (a AFB(1)), and a Fe3O4 magnetic core with a gold shell functionalized with 3-((2-mercaptoethylimino)methyl)benzene-1,2-diol and labeled with an AFB(1). The immunosensor was used for the detection of Aflatoxin B-1 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 AFB(1) 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. (c) 2012 Elsevier B.V. All rights reserved.