A sandwich-type electrochemical immunosensor based on RhPt NDs/NH2-GS and Au NPs/PPy NS for quantitative detection hepatitis B surface antigen

In this work, a sandwich-type electrochemical immunosensor was fabricated to quantitatively detect hepatitis B surface antigen (HBsAg). The immunosensor was based on Rh core and Pt shell nanodendrites loaded onto amino group functionalized graphene nanosheet (RhPt NDs/NH2-GS) as label and gold nanoparticles loaded onto polypyrrole nanosheet (Au NPs/PPy NS) as platform. RhPt NDs with abundant catalytic active sites because of the branched core-shell structure, RhPt NDs/NH2-GS as the label displayed high catalytic activity, amplifying the current signal of the immunosensor. Additionally, Au NPs/PPy NS enhanced the electron transfer and provided a good microenvironment to immobilize antibodies effectively, thus improving the sensitivity of the immunosensor. Based on above advantages, the immunosensor emerged a linear concentration ranging from 0.0005 to 10 ng/mL, a low detection limit of 166 fg/mL for HBsAg (S/N = 3) and good stability, selectivity, reproducibility. Furthermore, the satisfactory accuracy in analysis of actual serum samples implied the immunosensor had promising prospect in clinical analysis applications. (C) 2018 Elsevier B.V. All rights reserved.