Construction of a label-free COF/PTh/MB electrochemical immunosensor for the detection of CA-125

CA-125, as a tumor marker for ovarian cancer, plays an important role in rapid and sensitive detection in early diagnosis. Herein, a label-free electrochemical immunosensor based on a COF/PTh/MB nanocomposite was constructed for the detection of CA-125. The TAPB-DMTP-COF material, with its large surface area and stable porous framework, was used as the substrate. However, its poor conductivity hindered electron transfer. To address this, the conductive polymer PTh was combined with the COF to enhance the composite's conductivity. Meanwhile, MB was used as a signal probe, and differential pulse voltammetry (DPV) was adopted to measure the electrochemical signal. Under optimized experimental conditions, the proposed immunosensor exhibited excellent performance for CA-125 detection, with a detection range of 1-10 000 mU mL^-1, and a low detection limit of 0.34 mU mL^-1 (S/N = 3), providing a potential platform for clinical application.