Abstract
Lack of biorecognition elements significantly hinders the development of rapid detection methods for clavulanic acid (CA). To address this, we expressed Class A β-lactamases PC1 in vitro and demonstrated its high affinity for CA. Then we investigated the recognition mechanisms of PC1 for CA and identified key contact amino acids: Ser70, Lys73, Ser130, Glu166, and Lys234. Furthermore, PC1 was utilized as a novel biorecognition element to establish a "pseudo-immuno" lateral flow strip (LFS) for CA detection. Aggregation-induced emission fluorescence microspheres (AIE@FM) and biotin-streptavidin (Bio-SA) were integrated to improve the detection performance of PC1-based LFS. Results showed that the sensitivity (cut-off value) of PC1-based AIE(Bio-SA)-LFS was enhanced 2-fold and 4-fold compared to basic AIE@FM-LFS and traditional Au-based LFS, respectively. Eventually, the proposed PC1-based AIE(Bio-SA)-LFS was successfully verified in milk samples with a cut-off value of 20 ng mL-1. This study provides a powerful tool for on-site CA monitoring for the first time.