The application of the inexpensive and synthetically simple electrocatalyst CuFe-MoC@NG in immunosensors

In this study, we used inexpensive and synthetically simple electrocatalysts as replacements for conventional precious metal materials to reduce hydrogen peroxide (H₂O₂). We for the first time developed N-doped graphene-coated CuFe@MoC using one-step calcination of binary Prussian blue analogues (PBAs) with Mo⁶⁺ cationic grafting precursors. The synergistic interaction of CuFe PBA and MoC increased the catalytically active sites for H₂O₂ reduction. The catalyst was optimized in terms of the ratio of CuFe PBA to Mo⁶⁺, PVP content, and calcination temperature to improve its catalytic activity. When it was used to construct an electrochemical immunosensor for carcinoembryonic antigen (CEA) detection, polydopamine (CuFe-MoC@NG@PDA) was coated on its outer surface to increase the antibody loading and MoS₂-Au NPs were used as substrates to improve Ab₁ immobilization and accelerate electron transfer at the electrode interface, thereby improving the response signal of the immunosensor. Its concentration was linearly related to the response signal from 10 fg mL^-1 to 80 ng mL^-1, and the lowest limit of detection was 3 fg mL^-1. In addition, the immunosensor has acceptable selectivity and high stability. All data indicate that nanocomposites have electrocatalytic applications.