A sandwich-type electrochemical immunosensor using polythionine/AuNPs nanocomposites as label for ultrasensitive detection of carcinoembryonic antigen

A sandwich-type electrochemical immunosensor was developed in this study for sensitive detection of carcinoembryonic antigen (CEA) based on rGO/CS/AuNPs as a sensing platform and PTh-Au composites as signal labels. Reduced graphene oxide (rGO), Chitosan (CS) and AuNPs were layer by layer modified on glass carbon electrode (GCE), which effectively enhanced electron transfer and provided excellent large electrochemical active surface area. Polythionine-Au composites prepared by chemical reduction method greatly amplified electrochemical signal with high conductivity and large surface area. The prepared immunosensor showed high sensitivity, good stability and selectivity for detection of CEA with a wide range of 0.3 ng/mL to 30 ng/mL (R-2 = 0.9972) and a detection limit as low as 0.1471 pg/mL. Furthermore, this sandwich-type immunosensor might be as a versatile platform for reliable early cancer diagnostics clinical.