Structure engineering of lanthanide functionalized metal-organic frameworks: A versatile tool for the early diagnosis of pheochromocytomas and paragangliomas.

As a main extracellular metabolite of dopamine, 3-methoxytyramine (3-MT) is considered a potential biomarker of pheochromocytomas and paragangliomas. Therefore, the determination of 3-MT is of great significance in the early diagnosis of disease. However, it remains challenging for detecting 3-MT in consideration of sensitivity and accuracy. Here, a luminescent  Eu3+ functionalized metal-organic frameworks （Eu3+@Al-MOF）with ultra-high chemical stability was constructed based on postsynthetic modification. Such a rational design greatly enhances the fluorescence signal of Eu3+@Al-MOF and it is endowed with excellent properties as a luminescent sensor to detect 3-MT in urine system. Intriguingly, the strong red emitting derived from antenna effect was significantly interdicted upon addition of 3-MT through the interaction between 3-MT and the ligand. The proposed sensing system exhibited many appealing analytical performances, such as excellent selectivity, high sensitivity and quick response. Remarkably, the developed paper-based sensor not only provides a portable and reliable strategy for direct detection of 3-MT but also expands the application of visual analysis tools. This work represents the first effort in designing a luminescent sensor to determine the metabolite biomarker 3-MT level and provides a new method for biomedical analysis.