Ultrasensitive immunochromatographic strip assay for the detection of diminazene.

We prepared monoclonal antibodies (mAbs) against diminazene and used them in the development of a gold nanoparticle-based lateral-flow test (GNT) strip and indirect competitive enzyme-linked immunosorbent assay for the detection of diminazene in beef and beef liver samples. MAbs, which belong to the IgG2a subclass, had a half maximal inhibitory concentration of 0.04 ng mL-1. Based on cross-reactivity, mAb against diminazene was highly specific. The visual limit of detection (vLOD) of the GNT strip was 0.1 µg kg-1, and the cut-off value was 1 µg kg-1 in beef samples. The vLOD of the GNT assay was 0.1 µg kg-1, and the cut-off value was 2 µg kg-1 in beef liver samples. The average recoveries of diminazene ranged from 97.5% to 103.7% when using ic-ELISA. The accuracy of the developed GNT strip was confirmed by comparing the results with the ic-ELISA results. We developed a reliable GNT strip assay for the rapid detection of diminazene in beef and beef liver samples.