Spatially-resolved dual-potential sandwich electrochemiluminescence immunosensor for the simultaneous determination of carbohydrate antigen 19–9 and carbohydrate antigen 24-2

A new electrochemiluminescence (ECL) immunosensor based on spatially-resolved dual-potential technology was designed for the simultaneous determination of carbohydrate antigen 19–9 (CA 19–9) and carbohydrate antigen 24–2 (CA 242). [email protected] was used as the anodic probe, and Pt nanoparticle-functionalized graphitic carbon nitride nanosheets (g-C3N4@PtNPs) were used as the cathodic probe. Two spatially-resolved areas on the dual-disk glassy carbon electrode (DDGCE) were modified with a AuNPs film by electrodeposition to improve the conductivity of the sensing interface. By recording the ECL responses at two different excitation potentials, the linear range for CA 19–9 was determined to be 0.0001–10 U/mL, with a limit of detection of 31 μU/mL. The linear range for CA 242 was 0.0005–10 U/mL, with a limit of detection of 0.16 mU/mL. Moreover, the ECL immunosensor possessed high selectivity and stability and successfully detected CA 19–9 and CA 242 in real samples. This immunosensor provides a new platform for clinical immunoassays.