A novel electrochemical immunosensor based on CoS2 for early screening of tumor marker carcinoembryonic antigen

Nanocomposites have certain excellent properties compared with single nanomaterials, and have been widely used in electrochemical immunosensors in recent years. the active edge of CoS2 exposes the large surface area and can perform excellent catalytic performance by using the unique structure of carboxylated Multi-walled carbon nanotubes (MWCNTs) to disperse easily agglomerated CoS2. The -NH2 group of polyaniline (PANI) covalently immobilizes horseradish peroxidase (HRP) biomolecules on its membrane, which has a higher catalytic activity for H2O2 and further amplifies the signal. Based on carbon-based nanomaterials and Gold nanoparticles (Au NPs) as the immune platform, MWCNTs/CoS2@PANI-HRP composites were prepared to be sandwich-current electrochemical immunosensor with easy operation, high sensitivity, good selectivity and strong stability. Electrochemical detection was performed by cyclic voltammetry (CV) and alternating current impedance (EIS) and its electrochemical performance was studied. The experimental results show that the prepared composite material has good electrochemical performance. The linear range of the prepared electrochemical immunosensor is 0.001~40 ng/mL, and the linear equation is y=-62.40-9.25*logCCEA, R2=0.9948. The limit of detection was 0.33 pg/mL (S/N=3).