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

Abstract

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 a large surface area and can exhibit excellent catalytic performances by using the unique structure of carboxylated multi-walled carbon nanotubes (MWCNTs) to disperse the 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, a MWCNTs/CoS₂@PANI–HRP composite based sandwich-current electrochemical immunosensor was prepared with easy operation, high sensitivity, good selectivity and strong stability. Electrochemical detection was performed by cyclic voltammetry (CV) and alternating current impedance spectroscopy (EIS) and its electrochemical performance was studied. The experimental results show that the prepared composite material exhibits good electrochemical performance. The linear range of the prepared electrochemical immunosensor is 0.001–40 ng mL⁻¹, and the linear equation is y = −62.40 − 9.25 × log C_CEA, R² = 0.9948. The limit of detection was 0.33 pg mL⁻¹ (S/N = 3).