Electrochemical Immunosensor Based on Catalytic Activity of Nitrogen-doped Graphene Quantum Dots Supported by Graphene Nanoribbon Composite ‎for Carbohydrate Antigen ۱۵-۳ Detection

Due to the inherent properties of electrochemical immunosensors, they are widely considered to ‎detect various biomarkers. This study developed an electrochemical immunosensor via the ‎excellent catalytic effect of nitrogen-doped graphene quantum dot supported by graphene ‎nanoribbon (N-GQD/GNR) composite as a sensing platform. ‎Nafion was used as‎ a ‎binder for binding of‎ N-GQD/GNRon the electrode surface ‎. The modified electrode with N-GQD/GNR ‎composite was applied to develop the label-free electrochemical immunosensor for the ‎measurements of carbohydrate antigen ۱۵-۳ (CA۱۵-۳) biomarker. The catalytic activity of N-‎GQD/GNR nanocomposite increases the peak currents of the proposed immunosensor due to the ‎accelerated electron transfer between the sensing platform and probe. This immunosensor has a ‎wide linear range of ۰.۵ to ۱۵۰.۰ U mL-۱, with a detection limit of ۰.۱ U mL-۱. Also, the ‎proposed immunosensor has significant specificity, high sensitivity, and accuracy. The prepared ‎electrochemical immunosensor was used to detect CA۱۵-۳ protein in blood samples. ‎