High sensitivity graphene based terahertz biosensor for accurate detection of blood antigens using a novel multilayer radial structure.

This study presents the design and development of an advanced graphene-based biosensor for the precise detection of blood antigens using three novel structural configurations. The sensor integrates graphene with localized surface plasmon resonance (LSPR) technology to achieve high sensitivity and selectivity in complex biological environments. The proposed structures consist of graphene layers, a silicon dioxide dielectric layer, and a gold base layer, further enhanced with gold nanoparticles. Simulation results indicate that the sensor achieves an absorption rate exceeding 98% in the terahertz regime, with the highest sensitivity reaching 10,514.1 GHz/RIU for the first structure, while the second and third structures exhibit sensitivities of 5,461.7 GHz/RIU and 2,390 GHz/RIU, respectively. The sensor reliably detects concentrations of hemoglobin (C_Hb) antigen ranging from 20 to 260 ng/mL with high precision. A key advantage is its polarization independence, ensuring stable performance regardless of the incident wave's polarization angle. Additionally, the sensor maintains high angular stability, operating effectively across incident angles from 0° to 60°. This graphene-based platform holds significant promise for the early detection of blood disorders, including anemia, thalassemia, and certain cancers. With its high diagnostic accuracy, real-time monitoring capabilities, and cost-effectiveness, it presents a viable alternative to traditional diagnostic techniques, advancing personalized medicine and point-of-care applications. To validate the proposed design method, RLC Equivalent circuit modeling is used, and there is a good agreement.