Three-step post-synthetic modification metal-organic framework as a ratiometric fluorescent probe for the detection of creatinine

Abstract

Creatinine (Cre) measurement in biological fluids is an increasingly important clinical measure for evaluating renal insufficiency, thyroid dysfunction, and muscle injury. Therefore, a simple, fast, and reliable Cre analysis method is of great significance to human health. Herein, a novel ratiometric fluorescence sensor, Ag-Eu-MOF-808-EDTA, was synthesized by introducing ethylenediaminetetraacetic acid (EDTA), Ag + , and Eu 3+ into the framework of MOF-808 through three steps of post-synthesis modification, and was used to detect Cre in PBS buffer of pH 7.2 at 35 °C with a “turn-on” ratio response in the presence of various interfering ions and several biomolecules. In this strategy, the characteristic emission of Eu 3+ at 551 nm can be turned on due to coordination between Cre and Ag + , while emission at 613 nm is independent of Cre, which produces a significant ratio response change throughout the cycle. Experimental results showed that the ratio fluorescence sensor displayed a wide linear range for Cre from 0.5 to 350 μM with a low detection limit of 0.42 μM. Finally, a good recovery rate (96.7–102.9%) and appropriate relative standard deviation (RSD <2.39%, n = 3) were obtained during the determination of creatinine in real urine and serum. This work provides additional insights into the detection of creatinine in clinical blood samples. • Ag-Eu-MOF-808-EDTA was prepared by three-step post-synthetic modification. • The material was used for a ratiometric fluorescence sensing of creatinine. • The ratiometric sensor showed a wide linear range and low detection limit for Cre.