Dual-assist heterologous antigens screening: An effective strategy to improve the sensitivity of lateral flow immunoassay.

Heterologous strategy has promising applications in improving the sensitivity of competitive immunoassay. In this study, the potential heterologous coating antigens (HEA) were screened from eight imidacloprid (IMI) structural analogs based on the cross-reactivity (CR) of a prepared antibody. Computer-aided molecular modeling was used to predict the optimal HEA. Compared with the homologous coating antigen (HOA), the predicted HEA prepared from acetamiprid (CR = 0.23 %) increased the detection sensitivity of the enzyme-linked immunoassay and colloidal gold nanoparticle-based lateral flow immunoassay (HOA-Au-LFIA) by 5.6 and 4.1 times, respectively. Subsequently, the HEA and aggregation-induced emission fluorescent labels were integrated into a lateral flow immunoassay platform (HEA-AIE-LFIA). The limit of detection was 0.12 ng mL−1 for HEA-AIE-LFIA, which was 7.7-fold lower than that of HOA-Au-LFIA. Furthermore, HEA-AIE-LFIA was applied to detect IMI in food samples with excellent recoveries (86.41 %–111.25 %). Overall, this strategy of screening for superior HEA has great potential for improving LFIA sensitivity. [Display omitted] • The optimal HEA, gained by theoretical prediction, was validated by the experiment. • Excellent LFIA based on the optimal HEA and AIE-NPs was established. • LOD of HEA-AIE-LFIA was 7.7 times lower than those of HOA-Au-LFIA. • HEA-AIE-LFIA with good recovery accuracy was applied in food sample detection. [ABSTRACT FROM AUTHOR]