Electrosynthesized poly(1,5-diaminonaphthalene)/polypyrrole nanowires bilayer as an immunosensor platform for breast cancer biomarker CA 15-3

In this paper, an electrosynthesized bilayer film of polypyrrole nanowire and poly(1,5diaminonaphthalene) on a disposable screen-printing carbon ink electrode is presented. The inner polypyrrole nanowire layer had a large surface-to-volume ratio and high conductivity in the neutral medium, whereas the outer layer of poly(1,5diaminonaphthalene) had functional amino groups on the polymer chains. The combination of polypyrrole nanowire and poly(1,5diaminonaphthalene) showed a promising material for electrochemical biosensing. Here we reported an electrochemical immunosensor based on this approach for the purpose of detecting breast cancer biomarkers. The bilayer could enhance the surface coverage of antibody anti-CA 15-3 and consequently improve the sensitivity and stability of the immunosensors. The magnetic beads were used as carriers of labeled antibody anti-CA15-3 and HRP (horseradish peroxidase) in order to achieve an amplification of the signal. Under optimized conditions, the linear range of the immunoassay was 0.05-20 U mL−1 with a detection limit of 0.02 U mL−1 CA 15-3 antigen.