▎ 摘　　要

We here report the in-situ electrochemical deposition of silver nanoparticles (AgNPs) and a reduced graphene oxide (rGO) nanocomposite on the surface of an indium tin oxide (ITO) electrode. The nanocomposite modified ITO was used as a basic platform for the construction of a novel electrochemical biosensor for the detection of hydrogen peroxide (H2O2); where horseradish peroxidase (HRP) tagged antibodies acted as recognition elements for carcinoembryonic antigen (CEA). The AgNPs-rGO/ITO modified electrode remarkably outperformed a bare electrode because of its enhanced surface area and electrocatalytic activity, resulting in a notably amplified electrical signal for the detection of H2O2. Through a cyclic voltammetric (CV) technique, the detection limit of the sandwich type immunoassay configuration was found to be 214 mu M, with a linear range of 25-500 mu M, as compared to the non-sandwich system, which was 120 mu M with the same linear range. In contrast, the current-time response of the resulting sandwich-type immunoassay configuration showed a wider linear response to H2O2 in the range of 25-1450 mu M, with a detection limit of 5.3 mu M, while the non-sandwich system exhibited a linear range of 25-1355 mu M (R-2 = 0.9992), with a detection limit of 10 mu M. Therefore, the current-time response provided a more sensitive means of detecting H2O2. The resulting immunosensor also exhibited outstanding stability and reproducibility, as well as selectivity toward H2O2 in the presence of several interferences. (C) 2015 Elsevier B.V. All rights reserved.