Sandwich-type electrochemical immunosensor based on Au NPs/3D hierarchical porous carbon network and Au NPs/Cu9S8 nanocages for the detection of alpha-fetoprotein.

Alpha-fetoprotein (AFP), serves as a reliable and vital biomarker for precise diagnosis and effective monitoring of hepatocellular carcinoma, requires precise detection. Herein, a sandwich-structured electrochemical immunosensor was crafted, employing three-dimensional layered porous carbon modified with gold nanoparticles (Au NPs) as the substrate and Au NPs/Cu9S8 as the labeling compound for accurate and sensitive detection of AFP. Due to the effective coordination between the 3D carbon network, Au NPs, and hollow Cu9S8 nanocubes, the sandwich-structured electrochemical immunosensor was able to produce three distinct response signals via various detection techniques, demonstrating a broad linear range (0.0001-400 ng/mL), exceptional sensitivity, and a remarkably low detection limit of 2.63 fg/mL. Moreover, the constructed immunosensor could be used to detect AFP in human serum. This research may offer a novel material framework for developing highly sensitive immunosensors.