A highly selective and sensitive colorimetric uric acid biosensor based on Cu(II)-catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine

The development of a selective and sensitive sensor for uric acid (UA) is of great significance in diagnosing disorders and avoiding relevant complications. Herein, a new colorimetric sensing platform for the detection of UA was established by Cu2+-catalyzed TMB (3,3',5,5'-tetramethylbenzidine)-H2O2 system, in which H2O2 was produced from the catalytic reaction of UA by uricase. In this strategy, Cu2+ exhibited a highly efficient peroxidase-like activity and catalyzed the oxidation of TMB by H2O2 to produce a blue product, thus generating optical signals, which could be distinguished by naked eyes or detected through UV-vis spectrometer. The UA biosensor exhibited a linear response in the range of 1-100 mu M, with a detection limit of 0.64 mu M. The colorimetric sensor could discriminatively detect UA in human urine samples with the recoveries over 94.0%. The obtained results are consistent with those measured by biochemistry analyzer with the average relative error of 4.9%. The uricase involved and Cu2+-catalyzed TMB-H2O2 sensor offers the advantages of high selectivity and sensitivity, and no need of sample pretreatment. Therefore, the present UA biosensor has great potential in applications for biochemical analysis and clinical diagnosis. This strategy broadens the sensing application of Cu(2+)catalyzed TMB-H2O2 system. (C) 2016 Elsevier B.V. All rights reserved.