One-step synthesis of redox-active polymer/AU nanocomposites for electrochemical immunoassay of multiplexed tumor markers

•The POPD/Au and poly(VFc-ATP)/Au nanocomposites were synthesized by one-step process.•The nanocomposites were used to fabricate multiplexed electrochemical immunosensor.•The immunosensor for CEA and AFP detection was simple and sensitive.•This immunosensor performed well on detection of clinical serum specimens.

In this work, a simple and sensitive multiplexed immunoassay protocol for simultaneous electrochemical determination of alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) was designed using redox-active nanocomposites. As the redox-active species, the poly(o-phenylenediamine) (POPD)/Au nanocomposite and poly(vinyl ferrocene-2-aminothiophenol) (poly(VFc-ATP))/Au nanocomposite were obtained by one-step method which HAuCl4 was used as the oxidant. With Au nanoparticles (AuNPs), the nanocomposites were successful to immobilize labeled anti-CEA and anti-AFP as the immunosensing probes. The proposed electrochemical immunoassay enabled the simultaneous monitoring of AFP and CEA in a wide range of 0.01–100 ng mL−1. The detection limits was 0.006 ng mL−1 for CEA and 0.003 ng mL−1 for AFP (S/N=3). The assay results of serum samples with the proposed method were well consistent with the reference values from standard ELISA method. And the negligible cross-reactivity between the two analytes makes it possesses potential promise in clinical diagnosis.