Novel monoclonal antibody-based sensitive enzyme-linked immunosorbent assay and rapid immunochromatographic strip for detecting aflatoxin M1 in milk

Monoclonal antibody (n-iAb) that is specific to AFM1 was generated from the hybridoma cell line, 10F3C10, which was obtained by the fusion of mouse NS1 myeloma cells with the spleen cells of mouse that had been immunized with AFM1-bovine serum albumin (BSA). The 10F3C10 mAb is belong to the immunoglobulin G1 isotype. Both competitive direct and indirect enzyme-linked immunosorbent assay (ELISA) was utilized to characterize the mAb for AFM1. The concentrations of AFM1, AFB1 and AFG1 that caused 50% inhibition (IC50) of the binding of AFM1-horseradish peroxidase (AFMI-HRP) to the antibody were found to be 0.022, 0.310 and 2.12 ngimL, respectively. The immunochromatographic strip (immunostrip) assay with mAb-gold nanoparticle conjugates as a detection marker exhibited a visual limit of detection of 0.1 ng/mL for AFM1 and the analysis took a total of 10 min. Closely examining 17 milk-based samples using cdELISA revealed that four were slightly contaminated with AFM1 at concentrations from 0.002 to 0.054 ngimL. All milk samples were negative in the immunostrip test because the levels of contaminant were below the detection limit of the strip. Notably, the presented cdELISA and immunostrip methods are highly sensitive methods for detecting AFM1 in milk. (C) 2016 Elsevier Ltd. All rights reserved

Production of Monoclonal Antibody for Okadaic Acid and Its Utilization in an Ultrasensitive Enzyme-Linked Immunosorbent Assay and One-Step Immunochromatographic Strip

Okadaic acid (OA) is a common marine biotoxin that accumulates in bivalves and causes diarrhetic shellfish poisoning (DSP). This study generated a monoclonal antibody (mAb) specific to OA from a hybridoma cell line, 6BIA3, which was obtained by fusion of myeloma cells (P3/NS1/1-AG4-1) with spleen cells isolated from a BALB/c mouse immunized with OA-gamma-globulin. The 6BIA3 mAb belongs to the immunoglobulin GI (kappa chain) isotype. Both competitive direct and indirect enzyme-linked immunosorbent assays (ELISAs) were established for characterization of the antibody. The concentrations causing 50% inhibition of binding of OA-horseradish peroxidase to the antibody by OA were calculated to be 0.077 ng/mL in the cdELISA. A rapid and sensitive mAb-based gold nanoparticle immunochromatographic strip was also established. This proposed strip has a detection limit of 5 ng/mL for OA and can be finished in 10 min. Extensive analyses of 20 seafood samples with ELISA revealed that 10 were slightly contaminated with OA, with a mean concentration of 0.892 ng/g. Analysis of OA in shellfish samples showed that data acquired by the immunochromatographic strip agreed well with those acquired by the ELISA. The mAb-based ELISA and immunochromatographic strip assay developed in this study have adequate sensitivity and accuracy for rapid screening of OA in shellfish samples

Development of a Sensitive Enzyme-Linked Immunosorbent Assay and Rapid Gold Nanoparticle Immunochromatographic Strip for Detecting Citrinin in Monascus Fermented Food

Antibodies against citrinin (CTN) were generated from rabbits, which were injected with CTN-keyhole limpet hemocyanin (KLH). This work involved the development of a sensitive competitive direct enzyme-linked immunosorbent assay (cdELISA) and a rapid gold nanoparticle immunochromatographic strip (immunostrip) method for analyzing CTN in Monascus-fermented food. CTN at a concentration of 5.0 ng/mL caused 50% inhibition (IC50) of CTN-horseradish peroxidase (CTN-HRP) binding to the antibodies in the cdELISA. The capable on-site detection of CTN was accomplished by a rapid antibody-gold nanoparticle immunostrip with a detection limit of 20 ng/mL and that was completed within 15 min. A close inspection of 19 Monascus-fermented foods by cdELISA confirmed that 14 were contaminated with citrinin at levels from 28.6–9454 ng/g. Further analysis with the immunostrip is consistent with those results obtained using cdELISA. Both means are sensitive enough for the rapid examination of CTN in Monascus-fermented food products

Sensitive enzyme-linked immunosorbent assay and gold nanoparticle immunochromatocgraphic strip for rapid detecting chloramphenicol in food

Antibody specific to chloramphenicol (CAP) was produced from rabbit that had been immunized with CAP‐keyhole limpet hemocyanin (KLH). Using the antibodies, we established a sensitive direct competitive enzyme‐linked immunosorbent assay (dcELISA) and a gold nanoparticle immunochromatographic strip (immunostrip) for detection CAP in food samples. In the dcELISA, CAP at levels of 0.15 ng/ml causes 50% inhibition (IC₅₀) of the binding of CAP‐horseradish peroxidase to the antibodies. The overall analytical recoveries of CAP (0.25–100 ng/g) added to the honey or milk samples in the dcELISA were 81.9 and 73.7%, respectively. Onsite determination of CAP was accomplished by immunostrips with a detection limit of 0.5 ng/ml and completed within 10 min. Carefully studying 10 honey and 6 milk samples using the dcELISA and immunostrip indicated that all examined samples were negative for CAP. The presented dcELISA and immunostrip methods are sensitive enough for the rapid determination of CAP in the samples