A highly sensitive monoclonal antibody-based paper sensor for simultaneously detecting valnemulin and tiamulin in porcine liver.

Na, Guanqiong; Hu, Xiaofei; Sun, Yaning; Kwee, Sharon; Xing, Guangxu; Xing, Yunrui; Zhang, Gaiping

Valnemulin (VAL) and tiamulin (TIA) are pleuromutilin antibiotics used primarily for treating bacterial infections in swine or other food animals. Furthermore, VAL and TIA are also employed as feed additives to promote animal growth. However, the illegal use of VAL and TIA could cause a series of hazards to consumers. Here, VAL was designed to be conjugated with bovine serum protein to prepare immunogen. A highly sensitive monoclonal antibody that recognized both VAL and TIA has been successfully produced. Moreover, an immunochromatographic strip assay for rapidly screening VAL and TIA in porcine liver was established with visual detection limits (cutoff values) of 50 and 25 ng/g, respectively. The IC50 values calculated from the equation of the standard curve were 6.06 and 3.45 ng/g and the limits of detection were 0.96 and 0.29 ng/g for VAL and TIA. According to the recovery experiment results, the test strip exhibited acceptable accuracy and precision. Generally, the proposed strip provided a practical tool for the detection of VAL and TIA. PRACTICAL APPLICATION: We produced a highly sensitive monoclonal antibody and developed an immunoassay strip for simultaneously monitoring TIA and VAL. Additionally it was preliminarily confirmed that the rapid detection tool was suitable for screening TIA and VAL in porcine liver.