Three-dimensional gold nanoparticles/prussian blue-poly(3,4-ethylenedioxythiophene) nanocomposite as novel redox matrix for label-free electrochemical immunoassay of carcinoembryonic antigen.

We present a novel label-free electrochemical immunosensor for detecting carcinoembryonic antigen (CEA) based on three-dimensional (3D) gold nanoparticles/prussian blue-poly(3,4-ethylenedioxythiophene) (AuNPs/PB-PEDOT) nanocomposite, which was firstly synthesized by a simple redox reaction between the PB precursors and EDOT in an aqueous solution, followed by the electrochemical reduction of HAuCl 4 . The 3D nanocomposite not only possessed large surface area and favorable microenvironment, but also exhibited remarkable conductivity, stability and excellent biocompatibility. In addition, PB showed excellent redox properties. Then AuNPs/PB-PEDOT was used as both electron mediators and 3D matrices in the fabrication of immunosensor. FT-IR spectra were employed to confirm the formation of PB, PEDOT and PB-PEDOT. Significantly, the AuNPs/PB-PEDOT exhibited a 3D and hierarchically porous nanostructure, while the PB-PEDOT showed core-shell structure. The AuNPs/PB-PEDOT modified immunosensor showed good linearity with the concentration of CEA ranging from 0.05 to 40 ng mL −1 , and the detection limit was 0.01 ng mL −1 . Moreover, the prepared electrode displayed good selectivity, high stability and good repeatability, and showed great potential for application in real sample analysis. [ABSTRACT FROM AUTHOR]