RESUMEN
OBJECTIVE: To develop a rapid and sensitive fluorescent immunochromatographic strip for the detection of cefalexin residue. METHODS: The Eu-silica nanoparticles were synthesized by using RP-microemulsion technology. The Eu-silica nanoparticles conjugated with cefalexin monoclonal antibody was used as a fluorescent label. The fluorescent immunochromatographic strip for the detection of cefalexin based on competitive inhibition immunoassay format was developed. The cefalexin-ovalbumin and goat anti-mouse IgG were immobilized on the nitrocellulose membrane as the test line and control line. RESULTS: After experiment optimization, the developed strip could provide detection results within 30 min and the limit of detection of cefalexin was 25 ng·mL-1. There was no cross-reactivity with 12 kinds of antibiotics including cephalosporins and penicillin. CONCLUSION: The fluorescence immunochromatographic strip is rapid, sensitive, and easy to operate, which may be a powerful tool to detect antibiotics in the future.