Sensitivity enhanced terahertz plasmonic metasurface biosensor based on symmetrical graphene–gold–silver resonators for breast cancer biomarker detection

Breast Cancer continues to be one of the leading causes of cancer related death among women worldwide, highlighting that there is a significant need for novel non -invasive methods for screening and detecting early stage breast cancer. Conventional diagnostic methods, such as mammography and biopsy, have limitations including invasiveness, ionizing radiation exposure, and reduced sensitivity for early-stage tumors. This study proposes a novel method for breast cancer screening and detection using a Terahertz (THz) Metamaterial Biosensor that incorporates Graphene, Gold (Au), Silver (Ag), Copper (Cu) Nano-Structures to enable selective and sensitive biomarker detection by measuring the refractive index changes of the material. The Sensor Architecture has a hierarchical structure consisting of nested resonators (Circular Au Rings, Rectangular Ag Resonators, and Square Cu Rings) which are located on a Graphene-Coated Glass Substrate and were optimized to create Surface Plasmon Resonance (SPR) and EM Field Confinement in the THz Regime. Machine Learning and simulation results indicate that the proposed sensor achieves a sensitivity of 500 GHz/RIU and Figure of Merit (FOM) values ranging from 1.744 to 4.202 RIU⁻1 and detection limits below 1.01 RIU. The sensor’s absorption and resonance responses is modified via changing graphene’s chemical potential (0.1–0.9 eV), incidence angle (0°–80°), and resonator geometry (Square Ring Side Length 4.6–9.6 µm). The peak absorption reaches 57.518 % at 0.9 eV. An XGBoost model was employed to accurately predict sensor performance based on refractive index, incidence angle, and resonator size variation for which the R2 > 0.9997 was attained. This integration of plasmonic metasurface design and machine learning provides a robust, highly precise design for early breast cancer screening and detection with potential clinical translation and supporting the objectives of Sustainable Development Goal 3 (SDG 3): Good Health and Well-Being by promoting early diagnosis and improved healthcare outcomes.