A turn-on fluorescence sensor for creatinine based on the quinoline-modified metal organic frameworks

Creatinine (Cre) level is closely related to renal function of human. Therefore, it is of great significance to develop highly sensitive and selective tools for Cre determination. Herein, a turn-on fluorescence metal organic framework (MOF) sensor, which was synthesized by post-synthetic modification of 8-hydroxy-2-quinolinecarboxaldehyde (HQCA) and Al³⁺ toward UiO-66-NH₂, was applied to detect Cre. The turn-on of fluorescence was attributed to the formation of Lewis acid-base complexes between Cre and Al³⁺, which led to the interruption of energy transfer and electron transfer from UiO-HQCA to Al³⁺. Thus, the fluorescence quenching of UiO-HQCA-Al caused by Al³⁺ was recovered. Results showed that the sensor exhibited wide linear range (0.05-200 μM), high sensitivity (detection limit = 4.7 nM), fast response time (1 min), and high selectivity toward Cre. The practicability of the sensor was verified by detecting Cre in human serum and urine samples. The present work was the first attempt that MOF material was used as a fluorescence sensor to detect Cre, which exhibited great application prospects in clinical diagnosis of related diseases.