Electrochemical Immunosensor Based on Catalytic Activity of Nitrogen-doped Graphene Quantum Dots Supported by Graphene Nanoribbon Composite for Carbohydrate Antigen 15-3 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. as Nafion was useda binder for binding ofN-GQD/GNRon the electrode surfac. The modified electrode with N-GQD/GNR composite was applied to develop the label-free electrochemical immunosensor for the measurements of carbohydrate antigen 15-3 (CA15-3) 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 0.5-150.0 U ml-1, with a detection limit of 0.1 U ml-1. Also, the proposed immunosensor has significant specificity, high sensitivity, and accuracy. The prepared electrochemical immunosensor was used to detect CA15-3 protein in blood samples.