A novel sandwich-type immunosensor for detection of carcino-embryonic antigen using silver hybrid multiwalled carbon nanotubes/manganese dioxide

Abstract A novel sensitive sandwich-type nonenzymatical electrochemical immunosensor was fabricated for quantitative determination of the carcino-embryonic antigen (CEA). β-cyclodextrin/multiwalled carbon nanotubes (β-CD/MWCNTs) that were used as electrochemical sensing platform improved the surface of electrode to immobilize first antibodies (Ab 1 ) and enhanced the electrical conductivity. The synthetic silver nanoparticles-carbon nanotube/manganese dioxide (Ag NPs-MWCNTs/MnO 2 ) was used as labels of secondary antibodies (Ab 2 ) can improve the surface of electrode and enhance the electrochemical signal. MnO 2 and Ag NPs achieve dual signal amplification to improve the sensitivity effectively. Under the optimal conditions, the electrochemical immunosensor exhibited a wide linear range of 0.0001–0.5 ng·mL − 1 and 0.5–10 ng·mL − 1 respectively with a low detection limit of 0.03 pg·mL − 1 for CEA. The immunosensor was also successfully applied to detect the actual sample. This novel method may find huge potential application for the detection of CEA in the clinical diagnosis.