Performance Evaluation of Black Phosphorus and Graphene Layers Using Surface Plasmon Resonance Biosensor for the Detection of CEA Antigens

The biomarker carcinoembryonic antigen (CEA) plays an important role in the diagnosis and monitoring of cancer, like breast, surveillance, colon, and liver cancer. The highly sensitive surface plasmon resonance (SPR) sensor presented in this work uses two-dimensional (2D) materials: BP/graphene, and the franckeite layer integrated in a Kretschmann configuration. The sensor structure, which includes a copper (Cu) layer and a CaF2 prism, is intended to detect CEA in aqueous solutions with high accuracy. The proposed sensor’s performance was assessed using the transfer matrix method (TMM), with particular attention paid to important metrics like sensitivity, figure of merit (FoM), detection accuracy (DA), and penetration depth (PD). The proposed sensor achieved a sensitivity of 307.50 deg/RIU and a FoM of 61.62/RIU at a Rmin value of 4.20 × 10−5 a.u. at a 40 nm Cu thickness, operating at a wavelength of 633 nm. The maximum sensitivity of 348.07 deg/RIU was achieved at 47 nm Cu thickness with BP layer, while the graphene layer yielded maximum sensitivity of 314.32 deg/RIU at the same Cu thickness. The results show that adding 2D layered materials to symmetric SPR sensors greatly improves detection performance, providing a promising foundation for the detection of clinical biomarkers in the future.