Hapten design and strip sensor for rapid detection of linezolid in pork and animal feed

Linezolid (LNZ), an oxazolidinone antibiotic, is widely used in human clinical practice. However, due to insufficient regulatory oversight, some livestock farms illegally incorporate LNZ into animal feed, leading to residues in animal-derived foods and posing a food safety risk. In this study, through computer-assisted molecular simulation, a minimal epitope design strategy was proposed and an optimal novel hapten LNZ-1 was designed and identified. Subsequently, a high-affinity monoclonal antibody was successfully generated. The half-maximal inhibitory concentration of this antibody was 2.87 ng mL^-1. Based on the antibody, a lateral flow immunochromatographic assay (LFIA) strip was developed to detect LNZ residues in pork and animal feed. The visual limit of detection was 20 ng mL^-1 for both matrices, with recoveries from spiked samples ranging from 91.7% to 114.3%, and the LFIA strip showed satisfactory reliability for analyzing real samples. The results obtained using the LFIA strip were consistent with those from liquid chromatography-mass spectrometry analysis. This minimal epitope hapten design strategy provides a practical reference for preparing high-affinity monoclonal antibodies against complex chemical pollutants lacking active conjugation sites.