Sensitive detection of carcinoembryonic antigen (CEA) by a sandwich-type electrochemical immunosensor using MOF-Ce@HA/Ag-HRP-Ab₂ as a nanoprobe

Sandwich-type electrochemical immunosensor was one of the main methods for detecting carcinoembryonic antigen (CEA). In this work, using Ce-MoF as the skeleton precursor, hyaluronic acid (HA) was coated on the surface of Ce-metal organic framework (Ce-MoF), which loaded with silver nanoparticles (Ag NPs) and horseradish peroxidase (HRP) to catalyze H₂O₂ and double amplified the current signal. Thus, a sensitive sandwich-type electrochemical immunosensor (Ce-MoF@ HA/Ag-HRP) was designed to detect carcinoembryonic antigen (CEA). The designed immunosensor used Au NPs to enhance the ability of attach more the first antibody (Ab₁). This was due to Au NPs had good electrical conductivity and biocompatibility to accelerate electron transfer on the surface of the electrode. HA was riched in –COOH, –OH and had excellent biocompatibility, which can carry more Ag NPs to catalyze H₂O₂. Finally, the prepared sandwich-type electrochemical immunosensor had excellent biocompatibility and great catalytic performance. The immunosensor can be tested within 30 min and the logarithm of the current signal and CEA concentration showed a broad linear response range of 1 pg ml⁻¹–80 ng ml⁻¹, and the detection limit of CEA was 0.2 pg ml⁻¹. More importantly, the proposed immunosensor had good reproducibility, selectivity, stability and without matrix effect. This confirmed that the proposed immunosensor had broad prospects in early clinical trials. (paper)