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

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 (Ab1) and enhanced the electrical conductivity. The synthetic silver nanoparticles-carbon nanotube/manganese dioxide (Ag NPs-MWCNTs/MnO2) was used as labels of secondary antibodies (Ab2) can improve the surface of electrode and enhance the electrochemical signal. MnO2 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.