Colorimetric determination of cysteine based on inhibition of GSH-Au/Pt NCs as peroxidase mimic

In this work, we reported a facile and highly sensitive strategy for colorimetric detection of cysteine (Cys) based on the inhibition of catalytic activity of bimetallic nanoclusters induced by Cys. Glutathione-modified gold-platinum nanoclusters (GSH-Au/Pt NCs) with different Au/Pt molar ratios were prepared via one-pot approach and utilized as peroxidase mimics to catalyze the oxidation of 3,3',5,5'-tetramethyl benzidine (TMB) by H2O2. It has been found that Cys could inhibit the peroxidase-like activity of GSH-Au/Pt NCs efficiently, which leads to a decrease of the absorption intensity of the system at 652 nm with a fading of the blue color. These findings provide a worthy method for visualization and quantitative detection of Cys with different concentrations in the range from 0.5 to 30 mu M, and the detection limit is 0.154 mu M. Moreover, this method displays a promising application in colorimetric analysis of Cys in urine samples. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A facile and highly sensitive strategy for colorimetric detection of cysteine using bimetallic nanoclusters as peroxidase mimics was reported, with promising application in urine analysis. The method provides a valuable approach for visualization and quantitative detection of cysteine with different concentrations in a range of 0.5 to 30 μM, with a detection limit of 0.154 μM.