Ultrabright fluorescence probe mediated biosensor for rapid and ultrasensitive quantification of chloramphenicol in milk

The improper and excessive use of chloramphenicol has placed a heavy burden and adverse impact on the environment and human health. Herein, a fluorescent molecule with aggregation-induced emission characteristic is designed, synthesized, and encapsulated into polystyrene nanospheres, serving as an optical signaling probe in biosensors for ultrasensitive, rapid and accurate detection of chloramphenicol in milk. In this method, magnetic nanoparticles coupled with chloramphenicol antibody are used as immunomagnetic separation carriers. The polystyrene microspheres embedding aggregation-induced emission molecules are modified with complete antigen of chloramphenicol and used as stable and efficient signal probes. Chloramphenicol in sample and complete antigen modified-polystyrene microspheres are competitively bound to the immuno-magnetic carrier. The concentration is determined by the fluorescence intensity of the binding magnetic complex. This optical immunosensor presents an ultra-wide linear range (100 pg/mL–500 ng/mL), extraordinary sensitivity (limit of qualification was 100 pg/mL, 10-fold sensitive than enzyme-linked immunosorbent assay), and rapid detection speed (∼40 min). Accuracy is strong concordant with that of HPLC and ELISA in the test of milk samples. This strategy exhibits notable sensitivity, stability, specificity and reproducibility. The detection time is considerably shortened and the procedure is streamlined. It is a potential method for monitoring antibiotic contamination in a variety of settings, including the environment, food, and clinical circumstances.