Label-Free Refractive-Index-Based Detection of Breast, Leukemia, and Prostate Cancer Cells Using a Tetra-Core PCF SPR...

In this research, a high-performance plasmonic refractive index (RI) biosensor based on an external metal deposition (EMD) technique and photonic crystal fiber (PCF) platform for potential cancer detection is presented, investigated, and linked with real-time cancer cells. Variations in the RI of biological fluids are closely associated with pathological conditions, including cancer, due to changes in cellular composition and biomolecular concentration. The proposed tetra-core PCF-SPR biosensor operates within the biologically relevant RI range of 1.33-1.37, enabling the detection of subtle RI variations corresponding to various cancerous cells. The sensing mechanism of the proposed sensor is based on surface plasmon resonance (SPR) and analyzed using coupled mode light theory for both x- and y- polarized modes. Key sensing performance parameters, including confinement loss (CL), wavelength sensitivity (WS), amplitude sensitivity (AS), sensor resolution (SR), and figure of merit (FOM) are systematically evaluated. The biosensor reports a WS of 9769 and 9069 nm/RIU for x-pol. and y-pol., respectively, AS of 623.182 and 645.087 RIU-1 for x-pol. and y-pol. respectively, SR in the order of 10-5 RIU, coefficient of determination (R2) of 0.97 and 0.96, and FOM of 60.17 and 53.01 RIU-1 for x-pol. and y-pol., respectively. Thus, the proposed PCF-SPR biosensor exhibits a dynamic range of 0.04 RIU. The sensing results demonstrate high sensitivity and strong resonance characteristics, indicating the capability of the proposed biosensor for label-free and non-invasive detection of cancer-associated RI changes in biological fluids. Thus, the presented biosensor offers a promising approach for the highly sensitive label-free detection of early-stage cancer cells by photonics sensing application.