Ultrasensitive electrochemical immunoassay for carcinoembryonic antigen based on three-dimensional macroporous gold nanoparticles/graphene composite platform and multienzyme functionalized nanoporous silver label

• Ultrasensitive electrochemical immunoassay for detecting CEA was developed.
• 3D-AuNPs/GN was employed as the carrier of primary antibodies.
• Multienzyme functionalized nanoporous silver was used as signal enhancer.

Three-dimensional macroporous gold nanoparticles/graphene composites (3D-AuNPs/GN) were synthesized through a simple two-step process, and were used to modify working electrode sensing platform, based on which a facile electrochemical immunoassay for sensitive detection of carcinoembryonic antigen (CEA) in human serum was developed. In the proposed 3D-AuNPs/GN, AuNPs were distributed not just on the surface, but also on the inside of graphene. And this distribution property increased the area of sensing surface, resulting in capturing more primary antibodies as well as improving the electronic transmission rate. In the presence of CEA, a sandwich-type immune composite was formed on the sensing platform, and the horseradish peroxidase-labeled anti-CEA antibody (HRP-Ab2)/thionine/nanoporous silver (HRP-Ab2/TH/NPS) signal label was captured. Under optimal conditions, the electrochemical immunosensor exhibited excellent analytical performance: the detection range of CEA is from 0.001 to 10 ng mL−1 with low detection limit of 0.35 pg mL−1 and low limit of quantitation (LOQ) of 0.85 pg mL−1. The electrochemical immunosensor showed good precision, acceptable stability and reproducibility, and could be used for the detection of CEA in real samples. The proposed method provides a promising platform of clinical immunoassay for other biomolecules

Three-dimensional macroporous AuNPs/graphene complex (3D-AuNPs/GN) and functionalized NPS were prepared to immobilize Ab1 and Ab2 respectively and combined to fabricate a sandwich-type ultrasensitive electro-chemical immunosensor for detecting CEA.Figure optionsDownload as PowerPoint slide