Carbohydrate antigen 24-2 (CA242) as a biomarker played critical roles in early diagnosis of colorectal cancer. Herein, a quenching-typed electrochemiluminescence immunosensor based on resonance energy transfer strategy was proposed for ultrasensitive CA242 detection. CdS NCs exhibited good electrochemiluminescence performance which was used as ECL energy donors, while COFs with porous structure presented UV-Visible light absorption was used as energy acceptors, which could significantly quench the ECL signal of CdS NCs. The sandwich-typed immunosensor was constructed with thiolated CdS NCs as substrates for primary antibody (Ab1) immobilization and functionalized COFs as carrier to immobilize secondary antibody (Ab2). With CA242 antigen captured, the distance between CdS NCs and COFs was closed and shortened the electron transfer path, leading to the quenching of the ECL signal of CdS NCs. Under the optimal conditions, the proposed immunosensor represented wide linear, and the detection extent is 0.001 U/mL to 1000 U/mL. At the same time, the detection limit of CA242 antigen is 0.000183 U/mL (S/N=3). The immunosensor exhibited its feasibility for detection of CA242 and lays a good foundation for high sensitivity sensing of other disease biomarkers in clinical diagnosis in the future.

You have access to this article

Please wait while we load your content... Something went wrong. Try again?