A novel label-free electrochemical immunosensor based on functionalized nitrogen-doped graphene quantum dots for carcinoembryonic antigen detection

Publication date: 15 April 2017
Source:Biosensors and Bioelectronics, Volume 90
Author(s): Yuying Yang, Qing Liu, Yan Liu, Jianjian Cui, Hui Liu, Ping Wang, Yueyun Li, Lei Chen, Zengdian Zhao, Yunhui Dong
A novel and ultrasensitive label-free electrochemical immunosensor was fabricated for quantitative detection of carcino-embryonic antigen (CEA). The nitrogen-doped graphene quantum dots (N-GQDs) supported PtPd bimetallic nanoparticles (PtPd/N-GQDs) were synthesized by a simple and green hydrothermal procedure. Subsequently, PtPd/N-GQDs functionalized Au nanoparticles (PtPd/N-GQDs@Au) were prepared successfully via a self-assembly approach. Because of the synergetic effect present in PtPd/N-GQDs@Au, this novel nanocomposites has shown excellent electrocatalytic activity towards hydrogen peroxide (H2O2) reduction. Featuring good biocompatibility, excellent conductivity and large surface area, PtPd/N-GQDs@Au was applied as transducing materials to efficiently conjugate capture antibodies and amplify electrochemical signal. Under the optimal conditions, the proposed immunosensor was used for the detection of CEA with wide dynamic range in the range from 5 fg/mL to 50ng/mL with a low detection limit of 2fg/mL (S/N=3). Furthermore, this label-free immunosensor possesses high sensitivity, special selectivity and long-term stability, which shows promising application in bioassay analysis.



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