Ultrasensitive non-enzymatic immunosensor for carcino-embryonic antigen based on palladium hybrid vanadium pentoxide/multiwalled carbon nanotubes

A novel and sensitive sandwich-type non-enzymatic electrochemical immunosensor was fabricated for quantitative monitoring of carcino-embryonic antigen (CEA). Nanocomposite of stannic oxide/reduced graphene oxide was used as substrate material to increase the specific surface area and enhance the conductivity of the glassy carbon electrode. Gold nanoparticles (Au NPs) were introduced to link substrate materials and primary antibodies (Ab1) and accelerate the electron transfer in this system. At the same time, the palladium nanoparticles (Pd NPs)–vanadium pentoxide (V2O5)/multiwalled carbon nanotubes (MWCNTs) were used as the label of secondary antibodies (Ab2). This composite label has shown excellent catalytic activity towards the reduction of H2O2. The nanomaterial-based signal amplification can improve the sensitivity and lower the limit of detection. The proposed immunosensor showed wide linear range from 0.5pgmL−1 to 25ngmL−1 with limit of detection of 0.17pgmL−1. This novel immunosensor was used to analyze serum sample. The results indicated that this immunosensor may find huge potential application for quantitative detection of CEA in the clinical diagnosis. •Stannic oxide/reduced graphene oxide was first used in the immunosensor.•Pd–Vanadium pentoxide/multiwalled carbon nanotubes were first used as the labels.•Au was used to accelerate the electron transfer and as connecter.•The novel immunosensor possessed excellent sensitivity with a LOD of 0.17pgmL−1.