Enzyme mimicking inorganic hybrid Ni@MnO2 for colorimetric detection of uric acid in serum samples

Abstract

Reliable and inexpensive detection of uric acid in the absence of any peroxide or enzyme is very challenging for the development of a new cost effective clinical method. Herein, we report an easy, cost effective and nonenzymetic method for selective detection and quantification of uric acid using 3,3′,5,5′-tetramethylbenzidine (TMB) and a Ni@MnO₂ hybrid nanomaterial. The ultra-long porous core–shell Ni@MnO₂ hybrid nanomaterial, obtained from a simple redox transformation reaction between a prickly nickel nanowire and KMnO₄ solution, is reported for the first time. The growth mechanism is studied from time-dependent FESEM and TEM images. The hybrid nanomaterial exhibited intrinsic oxidase-like activity that helps catalytic oxidation of TMB (colourless) to a blue colored product which becomes colourless in the presence of uric acid. Moreover, this colorimetric method has been exploited for the assay of serum uric acid in real samples. Our proposed method can detect as low as 0.24 μM of uric acid with a linear range from 1 to 40 μM. Therefore, we believe that this method would be useful for the detection of uric acid in clinical laboratory.