Disposable amperometric immunosensor for simple and sensitive determination of aflatoxin {B1} in wheat

By Ma, Haihua; Sun, Jizhou; Zhang, Yuan; Xia, Shanhong
Published in Biochemical Engineering Journal NULL 2016

Abstract

Abstract A disposable and label-free electrochemical immunosensor was developed for aflatoxin {B1} (AFB1) determination in wheat based on immobilization of anti-AFB1 antibodies on the chitosan-gold nanoparticles (chitosan-AuNPs) modified gold microelectrode. The chitosan-AuNPs nanocomposite formed by one-step electrodeposition using chronoamperometry not only exhibited improved conductivity but also offered porous three-dimensional morphology, plentiful amine groups and good biocompatibility for antibody immobilization via covalent binding. To evaluate the effect of electrodeposition conditions on the surface structure and amperometric response of the chitosan-AuNPs modified microelectrode, both scanning electron microscope (SEM), cyclic voltammetry (CV) and energy dispersive spectroscopy (EDS) were studied under the different parameters of deposition potential and time. The morphology and electrochemical characterizations of the immunosensor were also investigated by atomic force microscopy (AFM) and CV. The developed immunosensor demonstrated good linearity between highly sensitive current response and {AFB1} concentration in two ranges of 0.2-2 ng mL?1 and 2-30 ng mL?1, with a detection limit of 0.12 ng mL?1 (S/N = 3). For assay of {AFB1} in wheat matrix, the linear range from 1.6 to 32 ng mL?1 was obtained considering the extraction of the sample.

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