Covalent post-synthetic modification of MOFs as a fluorescent sensor for the efficient detection of the biomarker of cystinuria.

Cystinuria is a genetic disorder, and in severe cases, it might lead to kidney failure. As an important biomarker for cystinuria, the level of arginine (Arg) in urine is a vital indicator for cystinuria screening. Therefore, it is urgently needed to detect Arg with high selectivity and sensitivity. In this work, a boric acid functionalized Zr-based metal-organic framework UiO-PhbA is prepared by grafting phenylboronic acid on UiO-66-NH 2 through a Schiff base reaction using a covalent post-synthesis modification (CPSM) strategy. The prepared UiO-PhbA exhibits a sensitive and specific fluorescence "turn-on" response to Arg and can be exploited to detect Arg in human serum and urine samples with a broad linear range of 0.6-350 µM and low limit of detection (LOD) of 18.45 nM. This study provides a new and reliable rapid screening protocol for sulfite oxidase deficiency-related diseases.