A luminescent metal-organic polyhedron for enzyme-free detection of uric acid

Rapid and reliable detection of uric acid (UA) in human biological fluids is important for the early screening and monitoring of metabolic-related diseases. In this work, an enzyme-free fluorescence sensing platform based on a discrete metal-organic polyhedron (MOP-15) was developed. MOP-15 exhibited favorable dispersibility and stable fluorescence behavior in solution. Upon the addition of UA, the fluorescence intensity of MOP-15 at 400 nm decreased markedly, mainly due to the inner filter effect (IFE) between UA and MOP-15. Under optimized conditions, a good linear response was observed over the range of 0.5-100 µmol L^-1, with a limit of detection (LOD) of 0.45 µmol L^-1. The system also exhibited good selectivity in the presence of common interfering species. When applied to real urine samples, good recoveries ranging from 92.5% to 108% were further obtained, with relative standard deviations (RSDs) below 6%. The proposed MOP-15-based fluorescent platform avoids reliance on natural enzymes and provides a simple, rapid, and convenient strategy for quantitative UA detection, with satisfactory accuracy, stability, and anti-interference capability. This work further expands the application of MOP-based luminescent materials in enzyme-free fluorescence sensing for preliminary urine analysis.