A stable Cd(II) metal-organic framework as a fluorescence sensor for nitrofuran antibiotics and vitamin B1/B9 in living cells.

The escalating threat of antibiotic resistance, fueled by drug misuse, coupled with the health risks posed by vitamin deficiencies, underscores a critical demand for efficient detection technologies. Herein, a novel V-shaped organic compound containing 2,1,3-benzothiadiazole (BTD) group, 4,4'-(benzo[c][1,2,5]thiadiazol-5,6-diyl)dibenzoic acid (H2BTDA), has been designed and synthesized. Further, a Cd(II) metal-organic framework (MOF) has been successfully prepared with the formula {[Cd(BTDA)]∙0.5DMF}n, (JXUST-61, where JXUST denotes Jiangxi University of Science and Technology). Interestingly, JXUST-61 exhibits a three-dimensional (4,8)-connected with alb-4,8-Fddd topological structure, which shows solvent-stability after soaking in organic solvents for at least 24 h. JXUST-61 is capable of rapidly detecting nitrofuran antibiotics (furacilin, nitrofurantoin, and furazolidone) via a fluorescence quenching effect with remarkably low detection limits (0.208, 0.265, and 0.168 μM, respectively). Simultaneously, it demonstrates outstanding fluorescence recognition for VB1 and VB9, achieving the detection limits of 0.189 and 0.291 μM, respectively. More importantly, it has good biocompatibility and low cytotoxicity to sense VB1 and VB9 in living cells. Therefore, JXUST-61 functions as a highly efficient multi-functional fluorescent probe, offering a novel strategy for the real-time monitoring of antibiotic residues and the diagnosis of vitamin deficiency-related health conditions.