An Immunosensor for Microcystins Based on Fe3O4 @Au Magnetic Nanoparticle Modified Screen-Printed Electrode

Coreshell Fe3O4@Au magnetic nanoparticles (NPs) were modified onto the surface of the screen-printed working electrode, and the antibody of microcystin-(leucine-arginine) (anti-MCLR) was immobilized on the film surface of Fe3O4@Au NPs by the adsorption between Au nanoparticles and antibody. Subsequently, bovine serum albumin (BSA) was used to block the non-specific adsorption sites of the electrode to obtain immunosensor for the detection of MCLR. The immunosensor was based on the direct competitive immunoassay format between the labeled agent of horseradish peroxidase-conjugated MCLR (MCLR-HRP) and the analyte. MCLR was determined by differential pulse voltammetry (DPV). Under the optimal experimental conditions, the peak current response decreased proportionally with the concentration of MCLR in the range of 0.79-12.9 mu g L-1 with a detection limit of 0.38 mu g L-1. The developed biosensor was used to determine MCLR in real water samples with the recoveries of standard additions of 95% 107%. The proposed immunosensor possesses the properties of fast, sensitive and portable, etc.