Tunable graphene-integrated metasurface biosensor with hybrid plasmonic-2D material coupling for dual cancer detection in terahertz regime

Abstract This study presents a vertically integrated terahertz metasurface biosensor that combines graphene with transition metal dichalcogenides for breast and colorectal cancer detection based on refractive index sensing. The resonant region uses a clustered cross geometry composed of four hollow circular rings and four solid circular resonators linked by orthogonal MoS2-coated rectangular strips on a graphene layer. Selected regions are coated with silver, gold, and copper, along with WS 2 , WSe 2 , and MoSe 2 , to control the electromagnetic response over 0.19 to 0.72 THz. Simulated absorption exceeds 98%. Resonance frequency tuning is accomplished by varying the graphene chemical potential between 0.1 and 0.9 eV and modifying the structure’s geometric parameters. For breast cancer detection, the sensor exhibits a sensitivity of 1000 GHz per RIU over refractive indices ranging from 1.385 to 1.401 RIU. Comparable sensitivity is observed for colorectal cancer detection within the 1.329 to 1.348 RIU range. The reported quality factors span from 1.5 to 1.63, yielding figures of merit up to 6.45 RIU⁻¹ and a minimum detection limit of 0.365. A Random Forest regression model predicts the sensor’s response under variations in incident angle and resonator geometry, achieving $$\:{R}^{2}>0.9996$$ and a root mean squared error below 0.003 across the evaluated dataset. Electric field simulations show frequency-dependent field concentration in the sensing region, which supports differentiation between dielectric properties assigned to healthy and malignant tissues in the model. The design uses electrically tunable graphene conductivity and multilayer material coupling to modify resonance behavior in a single device intended for label-free terahertz biosensing.