A novel lateral flow chromatographic platform for antibiotic assay based on multifunctional probes integrating dual-emission ratiometric fluorescent sensing with molecularly imprinted polymers

Ceftazidime (CFZ), a widely used antibiotic, can cause serious toxic side effects when administered in excessive doses. Thus, there is an urgent need to develop new strategies for sensitive and timely detection of CFZ. Herein, we report a novel lateral flow chromatography assay (LFCA) method based on dual-emission ratiometric fluorescent molecularly imprinted polymers (dF-MIPs) for CFZ assay in a portable, rapid and accurate manner. The dF-MIPs is a multifunctional composite probe that possesses the selective recognition capability derived from MIPs and the ratiometric signal calibration capacity enabled by two distinct quantum dots (QDs). Specifically, the dF-MIPs consists of blue-emitting carbon quantum dots (C-QDs) embedded in the core of silica nanospheres as a reference signal, and orange-emitting CdTe QDs located in the shell of imprinted mesoporous silica as a response signal. As the concentration of CFZ increases, the CdTe QDs fluorescence at 570 nm is quenched, while the C-QDs fluorescence at 440 nm remains constant. By integrating dF-MIPs with LFCA test strips (LFCA@dF-MIPs), we realized CFZ determination in real serum samples within 10 min. The linear range is 10–1000 μmol·L⁻¹, and the detection limit is 2.8 μmol·L⁻¹, fully covering the effective concentration range of CFZ in the clinical therapy of infectious diseases. Furthermore, combining LFCA@dF-MIPs with a smartphone provides a convenient, miniaturized, and digital platform for point-of-care testing of CFZ.