Jiayong Bao, Peipei Li*, A. M. Abd El‐Aty, Jing Zhao, Lingyuan Xu, Chenxi Guo, Jia Li, Xingmei Lei, Sensen Feng, Yi Liu, Si Chen, Fen Jin, Jing Wang, Lufei Zheng*, Zhen Cao, Bruce D. Hammock, Maojun Jin*

Food Safety and Health，2026

Abstract: 

Colloidal gold immunochromatography (CG-ICA) is distinguished by its cost-effectiveness and rapid detection capabilities. However, its key recognition components-antigens and antibodies-are typically produced through chemical synthesis or ascites induction techniques. These methods often lead to batch-to-batch variability and the risk of cell line loss, thereby limiting the production efficiency of antigens and antibodies. In this study, using atrazine as the target analyte, a novel colloidal gold test strip, AId/rAb-ICA (Anti-Idiotypic nanobody/recombinant full-length antibody-immunochromatographic assay), was successfully developed by employing an anti-idiotypic nanobody (AI-Nb-66) and a recombinant full-length antibody (ATR-rAb) to replace the traditional antigen-antibody pair in CG-ICA. The detection limit (LOD) of this test strip was 0.31 ng/mL. It was successfully validated in apples, celery, and scallions, with recovery rates ranging from 82.45% to 103.60% and coefficients of variation (CVs) not exceeding 7.80%. This study offers a new approach for atrazine detection and the development of colloidal gold test strips.