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

Fluorescent bovine serum albumin-protected gold nanoclusters ( [email protected] 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 [email protected] NCs, respectively, causing efficient quenching on the fluorescence of [email protected] NCs. The quenching mechanism can be attributed to the dual inner filter effect (IFE). Based on the dual IFE, [email protected] NCs were utilized as both peroxidase mimics and fluorescent reporters for H 2 O 2 detection and further for uric acid detection with uricase. Under optimal detection conditions, the method can be used to detect H 2 O 2 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.