High-affinity recombinant full-length antibody-based immunochromatographic strip assay for rapid and reliable detection of pyraclostrobin residues in food samples

In this study, a rapid and reliable gold nanoparticles immunochromatographic strip (GNPs-ICS) assay based on a full-length recombinant antibody (rAb) was established for pyraclostrobin detection in food samples. First, a hybridoma PY-C7 secreting pyraclostrobin-specific monoclonal antibody (mAb) was produced. The variable region sequences of PY-C7-mAb were obtained by PCR and Sanger sequencing and used for the rAb expression in HEK293(F) cells. By GNPs-ICS assay, the visual LOD of pyraclostrobin standards was 0.1 mg L−1 (rAb) and 0.2 mg L−1 (mAb). Validated by recovery test, the visual LOQ of pyraclostrobin could meet the MRLs of Chinese food safety standard in strawberry, banana and Chinese cabbage samples by GNPs-mAb/rAb-ICS, in which the rAb showed better sensitivity and stability. Moreover, the GNPs-rAb-ICS showed comparable reliability with LC-MS/MS for actual sample detection. Above all, GNPs-ICS assay based on the full-length rAb was qualified for rapid detection of pyraclostrobin in food samples.