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.