Ultra-small CuS Nanoparticles as Peroxidase Mimetics for Sensitive and Colorimetric Detection of Uric Acid in Human Serum

Abstract As the main final products of the purine metabolism in human body, uric acid (UA) usually presents in serum and urine. Thus, the level of UA in biology is closely related to human health. In this work, the ultra-small CuS nanoparticles (NPs) were demonstrated to possess intrinsic peroxidase-like activity towards 3,3',5,5'-tetramethylbenzidine (TMB) substrate in the presence of H2O2, which yielded the blue oxidized TMB (oxTMB) with strong absorption at 653 nm. Furthermore, H2O2 could be produced by the enzymatic reaction between UA and uricase to yield the blue oxTMB with the peroxidase mimetics activity of CuS NPs, which provided a sensitive and colorimetric method for UA detection with a linear range from 1.0 × 10−6 M to 1.0 × 10−4 M and a detection limit of 1.0 × 10−7 M. Moreover, the proposed method was successfully applied to the determination of UA in human serum samples, which supplied a similar result to the clinical method.