Dual-ligand Zr-based metal-organic framework for ratiometric fluorescence sensing and imaging of copper ion in biological system.

Excessive accumulation of copper ions in the human body is closely associated with various diseases, including gastrointestinal disorders, neurological dysfunction, and hepatorenal diseases. Thus, reliable detection techniques for Cu2+ in blood and cells are crucial for early diagnosis and pathology studies. In this work, a dual-ligand Zr-MOF (TCPP@UiO-66-(OH)2) was successfully synthesized in situ using tetrakis(4-carboxyphenyl)porphyrin (TCPP) and 2,5-dihydroxyterephthalic acid (H2BDC-(OH)2) as ligands via a simple one-pot method. This dual-ligand Zr-MOF was reported as a ratiometric fluorescence sensing probe for Cu2+ detection, featuring with single excitation and dual-emission. The green-emitting H2BDC-(OH)2 serves as an effective internal reference for efficient correction in complex environments, while TCPP provides active sites for Cu2+ recognition, with its red emission being selectively quenched by Cu2+. The fluorescence probe demonstrates excellent selectivity, high sensitivity, a broad linear detection range (1 uM-12 uM), and a low limit of detection (42 nM). Moreover, the developed fluorescence sensing platform has been successfully applied to Cu2+ detection in human serum and imaging in living cells, highlighting its significant potential for biosensing applications.