Development of a monoclonal antibody for the detection of xylazine in milk and its use in an immunochromatographic strip

Abstract

We prepared a monoclonal antibody (mAb) which was sensitive and specific against xylazine based on a new hapten. The 50%-inhibitory concentration (IC₅₀) of the mAb against xylazine was 0.399 ng mL⁻¹ and the mAb was of the IgG2b subclass. A cross-reactivity test showed that the mAb had very high specificity for xylazine. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and gold nanoparticle-based lateral-flow test (GNT) strip were developed for the rapid screening of xylazine in milk samples. The limit of detection (LOD) and cut-off value of the GNT assay were evaluated to be 20 and 200 ng mL⁻¹ in milk samples with the naked eye. The average recoveries of xylazine which was detected by the ic-ELISA ranged from 95.1% to 105.1%. Real samples were used to confirm the accuracy of the developed GNT strip. These results demonstrated that we had developed a very reliable method for rapid detection of xylazine in milk samples.