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A. V. Petrakova, A. E. Urusov, A. V. Zherdev, B. B. Dzantiev
Comparison
of techniqies for antibodies immobilization on the surface of magnetic
particles in pseudo-homogeneous immunoenzyme assay of aflatoxin B1
Abstract
Pseudo-homogeneous enzyme immunoassay (EIA) of aflatoxin B1 (AFB1) has
been realized with the use of conjugates between monoclonal antibodies against
AFB1and magnetic particles
(MP). The assay includes concentration of AFB1 from the tested sample on the
surface of the MP-antibody conjugate, binding of AFB1-peroxidase conjugate with
free sites of the antibodies, separation of formed complexes from unreacted
components by magnetic field, and registration of enzymatic activity for
peroxidase label bound with the MP. The preparations of antibody conjugates
were obtained by three ways, physical adsorption on native MP and covalent
binding to MP covers formed by oleic acid or polystyrene, and compared. EIA for
these conjugates has limits of AFB1 detection equal to 2.6; 0.4 and 0.6 ng/mL,
respectively. The pseudo-homogeneous EIA format enables reduction of
immunoreagents incubation to 5 min (total duration of the analysis is 20 min)
and allows to concentrate the analyte from the tested samples. These features
determine advantages of the proposed assay as a tool for high sensitive control
of toxic contaminants in food stuffs.
Key words: magnetic
nanoparticles, immunoenzyme assay, immobilization of antibodies, aflatoxin B1.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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