Development of monoclonal antibody-based colloidal gold immunochromatographic assay for analysis of halofuginone in milk

A highly sensitive, specific, and rapid immunochromatographic assay for halofuginone (HFG) has been developed. A well-characterized immunogenic conjugate of HFG with bovine serum albumin was produced using the N,N″-Carbonyldiimidazole method. A sensitive monoclonal antibody specific for HFG was then generated by immunizing BALB/c mic with the HFG conjugate. The antigen, HFG-CDI-ovalbumin and goat anti-mouse IgG were attached to a nitrocellulose membrane as the test line and the control line, respectively to produce an immunochromatographic test strip for the rapid detection of HFG in milk. Under optimized conditions, the detection limits of the semi-quantitative test strip for HFG were as low as 50 ng/mL in 0.01 M PBS (pH 7.4) and 100 ng/mL in milk. All the results were obtained within 5 min. The newly developed immunochromatographic assay provides a sensitive, rapid, and specific procedure for on-site screening for HFG.