Detecting uric acid base on the dual inner filter effect using BSA@Au nanoclusters as both peroxidase mimics and fluorescent reporters

This scientifically describes a fluorescent method detecting UA based on the dual IFE utilizing BSA@Au Nanoclusters as peroxidase mimics and fluorescent reporters. [Display omitted] •A facile fluorescence strategy for H2O2 and uric acid (UA) detection has been established.•BSA@Au NCs catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to quench its fluorescence by the dual inner filter effect (IFE).•A highly selective method with a detection limit of 0.39 μM for UA was successfully developed. Fluorescent bovine serum albumin-protected gold nanoclusters (BSA@Au NCs) can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue oxTMB for its peroxidase-like activity. The two absorption peaks of oxTMB overlapped with the excitation and emission peaks of BSA@Au NCs, respectively, causing efficient quenching on the fluorescence of BSA@Au NCs. The quenching mechanism can be attributed to the dual inner filter effect (IFE). Based on the dual IFE, BSA@Au NCs were utilized as both peroxidase mimics and fluorescent reporters for H2O2 detection and further for uric acid detection with uricase. Under optimal detection conditions, the method can be used to detect H2O2 ranging 0.50–50 μM with a detection limit of 0.44 μM and UA ranging 0.50–50 μM with a detection limit of 0.39 μM. The established method had been successfully utilized for the determination of UA in human urine, with massive potential in biomedical applications.