Label-free electrochemical immunoassay for α-fetoprotein based on a redox matrix of Prussian blue-reduced graphene oxide/gold nanoparticles-poly(3,4-ethylenedioxythiophene) composite

Herein, a stable and sensitive label-free electrochemical immunosensor for detecting α-fetoprotein (AFP) was proposed based on gold nanoparticles-poly(3,4-ethylenedioxythiophene)/Prussian blue-reduced graphene oxide (AuNPs-PEDOT/PB-rGO) nanocomposite as sensing substrate. PB was used as the electron transfer mediator to provide the electrochemical signal. By utilizing rGO as the supporting material for PB, the stability and intensity of the redox signal were greatly improved. The incorporation of highly conductive AuNPs-PEDOT can further enhance the electrochemical signal and its stability. Electrochemical test showed the anodic current of AuNPs-PEDOT/PB-rGO modified electrode could remain up to 89.45% after 100 cyclic voltammetries . The assembly of PB-rGO and AuNPs-PEDOT exhibited 3D nanostructure and showed high specific surface area, which could effectively capture the antibody of AFP. With the advantages of AuNPs-PEDOT/PB-rGO nanocomposite, the prepared immunosensor showed a sensitive response to AFP in a linear range from 0.01 to 50   ng   mL −   1 with a low detection limit of 3.3   pg   mL −   1 (S/N   =   3). The proposed immunosensor also has been employed to determine AFP in human serum with satisfactory results. These excellent properties make the AuNPs-PEDOT/PB-rGO nanocomposite an ideal interface for efficient biomarkers detection.