Visual detection of uric acid in serum through catalytic oxidation by a novel cellulose membrane biosensor with...

Uric acid (UA) serves as an important biochemical marker of various diseases, making the development of a novel method for its rapid and straightforward visual detection highly valuable. In this study, a uricase-based cellulose membrane biosensor (UCMB) was constructed by immobilizing uricase via a Schiff base reaction and nitroblue tetrazolium chloride (NBT) through adsorption. The UCMB detects UA through a mechanism in which uricase catalyzes the oxidation of UA, generation O₂^-· radicals that subsequently oxidize NBT to formazan, producing a distinctive color change from yellow to purple. The UCMB demonstrated successful visual detection of UA within 15 min, allowing for rapid naked-eye analysis. Additionally, the biosensor quantitatively detected UA over a broad linear range from 0 to 1000 μM, with a low detection limit of 3.88 μM. Most notably, the UCMB has accurately measured UA in human serum samples, comparable to the results from a commercial UA meter. These findings suggest that the UCMB can serve as a simple and reliable tool for early diagnosis of UA-related diseases.