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 0.01-100ngmL-1. The detection limits was 0.006ngmL-1 for CEA and 0.003ngmL-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.
Liu, Z., Rong, Q., Ma, Z., & Han, H. (2015). One-step synthesis of redox-active polymer/AU nanocomposites for electrochemical immunoassay of multiplexed tumor markers. Biosensors and Bioelectronics, 65, 307–313. https://doi.org/10.1016/j.bios.2014.10.012