OICC Press International Journal of Industrial Chemistry 2228-5547 17 2 2026 06 30 Carbon Dot-Assisted Electrochemical Immunosensor for Precise and Sensitive Measurement of Carcinoembryonic Antigen as a Tumor Biomarker 10.57647/IJIC.2026.1702.10 EN Maryam Refaiee Department of Chemistry, NT.C., Islamic Azad University, Tehran, Iran Fariba Tadayon Department of Chemistry, NT.C., Islamic Azad University, Tehran, Iran Hasan Bagheri Department of Chemistry, NT.C., Islamic Azad University, Tehran, Iran Journal Article 2026 06 30 This research introduces a straightforward electrochemical system with enhanced sensitivity for identifying carcinoembryonic antigen (CEA). To construct the sensing interface, the Glassy Carbon Electrode (GCE) surface was first covered with Au@CDs and then coupled with CEA antibodies, providing the platform’s biological recognition capability. The oriented immobilization of antibodies enhanced the biosensor’s recognition efficiency. The fabricated sensor was comprehensively analyzed using TEM, FTIR spectroscopy, and EIS. Following optimization, the developed sensor provided a linear quantitative response between 0.01 and 100 ng mL⁻¹ and reached a detection sensitivity down to 3.5 pg mL⁻¹.