Enzyme cascade nanozyme based colorimetric sensor for detection of uric acid as a biomarker of hyperuricemia

A Cr-doped VO 2 nanobelt (Cr/VO 2 ) with remarkable peroxidase-like activity was synthesized and coupled with uricase to catalyze the cascade reaction for  detection of uric acid. Notably, the affinity of Cr/VO 2 for 3,3',5,5'-tetramethylbenzidine dihydrochloride hydrate (TMB) and hydrogen peroxide (H 2 O 2 ) is tenfold and 20-fold higher, respectively, than that of horseradish peroxidase (HRP). The Cr/VO 2 exhibits highly reactive and stable peroxidase activity at temperatures of 20-60 ℃. Thus, the reaction catalyzed by Cr/VO 2 can be carried out at room temperature, greatly simplifying the testing process. This enzyme cascade nanozyme based colorimetric assay enables the selective and simple detection of uric acid within 30 min with a detection limit of only 0.34 μM, and has an observable potential in clinical applications. Graphical abstract