▎ 摘　　要

In this study, we present a novel approach to prepare of a colorimetric chemical sensor for H2O2 and a glucose biosensor basing on the use of peroxidase-like activity of silver nanoparticles decorated on reduced graphene oxide sheets (AgNPs@rGO) nanocomposite. Herein, AgNPs@rGO nanocomposite was synthesized by a one-step hydrothermal reducing method and its physico-chemical properties were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Ultraviolet-visible spectroscopy (UV-Vis), Fourier-Transform Infrared spectroscopy (FT-IR) and Energy Dispersive X-ray spectroscopy (EDX). Obtained evaluation results shown that the synthesized AgNPs/rGO nanocomposite has performed an efficient peroxidase-like activity for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMBred) by H2O2, leading to the oxidized form (TMBox) which presents a typical blue color (maximum of absorbance at lambda(max) = 655 nm). A colorimetric assay for H2O2 detection was designed and fabricated with a limit of detection of 20 mu M. Moreover, we have used of AgNPs/rGO nanocomposite combining with glucose oxidase (GOx) to develop of a colorimetric glucose biosensor with a low limit of detection of 40 mu M and a linear dynamic range from 125 mu M to 1 mM. This glucose test was applied to the detection of glucose in human serum samples. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).