Ultrasensitive electrochemical immunosensor for quantitative detection of HBeAg using Au@Pd/MoS2@MWCNTs nanocomposite as enzyme-mimetic labels

A sensitive sandwich-type electrochemical immunosensor for the detection of hepatitis B e antigen (HBeAg) was successfully developed based on the gold@palladium nanoparticles (Au@Pd NPs) loaded by molybdenum disulfide functionalized multiwalled carbon nanotubes (Au@Pd/MoS 2 @MWCNTs). The resultant nanocomposites not only possessed high specific surface area and good biocompatibility , but also exhibited excellent electro-catalytical property. Au NPs functionalized porous graphene oxide (p-GO@Au) were used as sensing platforms and primary antibodies carriers, which can accelerate the electron transfer and improve the load capacity of primary antibodies (Ab 1 ), improving the sensitivity of the immunosensor. Under optimal conditions, the designed immunosensor could detect target HBeAg concentration in the range from 0.1pg/mL to 500   pg/mL, with a low detection limit of 26   fg/mL (S/N = 3) for HBeAg. Additionally, the designed immunosensor showed excellent specificity, good reproducibility and acceptable stability. The satisfactory results in analysis of human serum samples indicated that it had potential application in clinical monitoring of tumor markers.