A dual amplification electrochemical immunosensor based on HRP-Au@Ag NPs for carcinoembryonic antigen detection

Abstract

A sensitive sandwich-type electrochemical immunosensor based on dual amplification strategy was constructed. The dual amplification strategy has been used secondary antibody(Ab2)-horseradish peroxidase(HRP)-Au@Ag nanoparticles (Au@Ag NPs) for carcinoembryonic antigen(CEA) detection. Ab2-HRP-Au@Ag NPs as dual amplification markers triggered the disproportionation of H2O2, which could facilitate the catalytic oxidation of hydroquinone to quinone(BQ). In addition, due to their large surface area and excellent conductivity, nitrogen-doped graphene were used as a platform to firmly assemble primary antibody (Ab1). Above mentioned generated amout of BQ are corresponding to trace CEA, resulting in the highly electrochemical reduction signal. Under the optimal conditions, the linear range of CEA concentration was 0.0001–100 ng mL−1, and the limit of detection (LOD) could be as low as 0.05 pg mL−1. Importantly, the immunosensor also showed acceptable stability, reproducibility and selectivity.