A Novel Turn-On Fluorescence Probe Based on Cu(II) Functionalized Metal-Organic Frameworks for Visual Detection of Uric Acid.

As an important biomarker in urine, the level of uric acid is of importance for human health. In this work, a Cu(II) functionalized metal-organic framework (Cu ²⁺ @Tb-MOFs) is designed and developed as a novel fluorescence probe for wide-range uric acid detection in human urine. The study shows that this fluorescence platform demonstrated excellent pH-independent stability, high water tolerance, and good thermal stability. Based on the strong interaction between metal ions and uric acid, the designed Cu ²⁺ @Tb-MOFs can be employed as efficient turn-on fluorescent probes for the detection of uric acid with wide detection range (0~10 ⁴ µM) and high sensitivity (LOD = 0.65 µM). This probe also demonstrates an anti-interference property, as other species coexisted, and the possibility for recycling. The sensing mechanisms are further discussed at length. More importantly, we experimentally constructed a molecular logic gate operation based on this fluorescence probe for intelligent detection of uric acid. These results suggest the Cu(II) functionalized metal-organic framework can act as a prominent candidate for personalized monitoring of the concentration of uric acid in the human urine system.