Label-free and selective sensing of uric acid with gold nanoclusters as optical probe.

Clinically, the amount of uric acid (UA) in biological fluids is closely related to some diseases such as hyperuricemia and gout, thus it is of great significance to sense UA in clinical samples. In this work, red gold nanoclusters (AuNCs) with relatively high fluorescence quantum yield and strong fluorescence emission were facilely available using bovine serum albumin (BSA) as template. The fluorescence of BSA-protected AuNCs can be sensitively quenched by H2O2, which is further capable of sensing UA through the specific catalytic oxidation with uricase, since it generates stoichiometric quantity of H2O2 by-product. The proposed assay allows for the selective detection of UA in the range of 10-800 μM with a detection limit of 6.6 μM, which is applicable to sense UA in clinical samples with satisfactory results, suggesting its great potential for diagnostic purposes.