▎ 摘　　要

Developing electrochemical biosensor, particularly for high sensitive recognizing and detecting tumor marker at low level under benign conditions, is highly desired, but still remains a severe challenge. In this communication, we report a dual-signaling ratiometric method for sensitive detection of carcinoembryonic antigen (CEA) based on gold nanoparticles (Au NPs) functionalized Cu2S-CuS/graphene composite (Au-Cu2S-CuS/graphene) as the matrix material and carboxyl-Au nanoparticles (Au-COOH) functionalized mesoporous CeO2 nanoparticles (Au-CeO2) supported toluidine blue (TB) complex as signal label. The oxidation peak current of Cu2S-CuS decreases with the increase of CEA concentration, while the oxidation peak current of TB increases. The change of dual signals "Delta I = Delta I-TB + vertical bar Delta ICu2S-CuS vertical bar" (Delta I-TB and vertical bar Delta ICu2S-CuS vertical bar are the change values of the oxidation peak currents of TB and Cu2S-CuS, respectively) is used as the response signal for quantitative determination of CEA. Notably, the linear range is 0.001 similar to 100 ng/mL with a detection limit of 0.78 pg/mL (S/N = 3). The ratiometric electrochemical system provides an extremely simple strategy for detecting tumor markers in a reliable, facile, sensitive, and specific manner, which has a promising application for quantitative detection of other tumor markers in clinical diagnosis. (C) 2017 Elsevier B.V. All rights reserved.