Intelligent graphene–silver–gold terahertz metasurface biosensor for glucose and colorectal cancer screening and early detection using 1D-CNN-enhanced modeling
摘要
The increasing incidence of colorectal cancer and diabetes has provided a strong demand in developing non-invasive biosensors that can detect multiple biomarkers, such as glucose and colorectal cancer, with high levels of sensitivity and reliability. A hybrid terahertz (THz) metasurface biosensor based on a graphene/silver/gold architecture is proposed to address this need for simultaneous detection of glucose and colorectal cancer biomarkers. The biosensor consists of a multi-resonator design which includes a Y-shaped Silver Resonator, a concentric Circular Silver Ring, and a Square Gold Ring, mounted on a Silicon Dioxide substrate coated with a Graphene layer on the bottom surface. The designed structure was optimized using COMSOL Multiphysics to improve the resonance performance. The optimized structure exhibited a sensitivity of 2,000 GHz/RIU, a Figure of Merit (FOM) of 15, and a detection limit of 0.118 RIU, and showed a frequency shift of 25 GHz for glucose and 40 GHz for colorectal cancer biomarkers within the 0.1–10 THz frequency range. Strong electromagnetic field concentrations were observed at the resonance frequency of 0.514 THz for glucose and 0.68 THz for colorectal cancer detection. The Linear correlation between refractive index variations and resonance frequency shifts was observed with R2 value of 0.842 and 0.925 for glucose and colorectal cancer biomarker detection, respectively. The tunable graphene layer allowed the modulation of transmittance from 97.1% to 37.8% by changing the chemical potential from 0.1 to 0.9 eV. In addition, the integration of a One-Dimensional Convolutional Neural Network (1D-CNN), significantly increased the predictive accuracy and operational robustness of the biosensor. The CNN model achieved R2 values greater than 0.9998 and Mean Squared Error (MSE) values lower than 0.000005 for incident angle ranging from 0° to 80°. In conclusion, the proposed biosensor represents a promising approach to develop a compact, label-free, and intelligent sensing platform for Point-of-Care Diagnostics and Next-Generation Non-Invasive Biomedical Applications contributing to the Sustainable Development Goal 3 (SDG 3) on good health and well-being.