A UOx@HMnO₂ biozyme-nanozyme driven electrochemical platform for specific uric acid bioassays

Uric acid (UA) is a key end product of purine metabolism in the human body, and its abnormal levels are associated with many diseases, so accurate monitoring is essential. Existing detection methods have many limitations. For example, chromatography is cumbersome, time-consuming, and not cost-effective, while serum uric acid analysis requires specialized equipment and venous blood collection. In the field of uric acid sensors, electrochemical detection is commonly used but prone to interference, and nanomaterials offer improvements but are complicated to modify. To better block interference via an easily-made nanocomposite-based system, in this study, MnO₂ with peroxidase-mimicking activity was used as a protective shell to encapsulate natural uric acid oxidase (UOx), realizing a good combination of nanozymes and biocatalysts. UOx can selectively catalyze UA and generate H₂O₂, and the MnO₂ nanozymes can make up for the insufficiency of UOx, and the two main components synergistically enhance the activity of UOx@HMnO₂, resulting in ultra-high performance. This provides a simple and general method for the preparation of efficient hybridized biocatalysts in the fields of biosensors and biocatalysis. The detection limit of the fabricated uric acid sensor is as low as 0.74 μM, and the concentration of the actual sample is consistent with that of mass spectrometry, which provides a means of non-invasive detection of uric acid with high sensitivity, high specificity and good accuracy.