Electrochemical immunosensor based on C-ink/CD/ZnO-labeled-Ag@PPy/PEG composite for CA-125 ovarian cancer biomarker detection

In this work, we demonstrated a novel cancer antigen 125 (CA125) biomarker detection based on electrochemical immunosensor. The biomarker on conductive composite materials of carbon ink/carbon dot/zine oxide (C-ink/CD/ZnO) was employed as an electrode platform by using ITO substrate to enhance the interaction of antibodies (Ab) with supporting catalytic performance of ZnO as a labeling signal molecule. They were a scientist attention for biosensor with chemical stability, strong biocompatibility, high conductive signal, and accuracy. Moreover, the nanocomposite of silver@polypyrrole (Ag@PPy) was used as a potential redox mediator. The labeled construction with Ag@PPy was more accuracy than that of a free-labeled.  The created immunosensor was a wide linear range as 100 ng·mL⁻¹− 0.001 fg·mL⁻¹ and a low limitation of detection as 0.1 fg·mL⁻¹ under the optimal condition. This suggested that the immunosensor is considered to be an accurate and efficient diagnostic tool for CA125 and other biomarkers detection in actual sample analysis for clinic.