Preparation of monoclonal antibody against penicillic acid (PA) and its application in the immunological detection.

The high content of Penicillic acid (PA) in the feed pose threat to human health and cause serious losses to economic wealth through the enrichment effect of the food chain. The reliable and rapidly detection of PA is of significant importance to ensure food safety. In this study, indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and immunochromatographic test strips (ICTS) were established for PA determination based on anti-PA mAb secreted by 4H9 cell line. The linear range of ic-ELISA detection was 0.12-1.95 μg/mL, and the limit of detection (LOD) was 0.03 μg/mL. Then, conventional gold nanospheres (AuNS) with the average diameter of 20 nm were synthetized and AuNS-based strip was developed for rapidly detection of PA. The visual LOD (vLOD) of the AuNS-based strip was 3.9 μg/mL and the assay time of visual evaluation was less than 10 min without any instrument. To enhance the signal sensitivity of the ICTS, the larger size (about 85 nm) of gold nanoflowers (AuNFs) was prepared in our work, and was used as higher signal reporter to establish the AuNF-based strip for PA determination. Fortunately, the vLOD of AuNF-based strip was 0.97 μg/mL, which was approximately 4-fold lower than that of traditional AuNS-based strip. In summary, the rapid and sensitive immunoassays established in this study could be applied to detect and analyze the contamination of PA toxin in real food samples.