Gold and titanium dioxide enhanced PCF SPR biosensor for early breast cancer detection in near infrared spectrum

Breast cancer is a major public health concern, with early detection significantly increasing the survival rate. This study focuses on the development of a photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor for detecting breast cancer cells, specifically MDA-MB-231 and MCF-7 cell lines. The proposed circular shaped biosensor is coated with gold (Au) and titanium dioxide (TiO2), where an Au layer is inserted over the fused SiO2. TiO2 is used as an adhesion layer which is covered by an analyte layer. There is a perfectly matched layer (PML) for absorbing scattered light from the internal structure. Using COMSOL Multiphysics, the biosensor's geometrical design was optimized, and finite element method (FEM) simulations were performed to evaluate its performance. The proposed biosensor operates within the refractive index (RI) range of 1.385 to 1.401, targeting breast cancer cell detection. Key performance metrics such as wavelength sensitivity (WS), amplitude sensitivity (AS), sensor resolution (SR), and figure of merit (FOM) were assessed. The proposed biosensor demonstrated the highest WS for MCF-7 of 29,285.17 nm/RIU in x polarization and 25,000 nm/RIU in y polarization. Similarly, the highest AS of 2136 RIU−1 in x polarization and 2975 RIU−1 in y polarization was achieved for MCF-7. The proposed biosensor showed exceptional FOM of 127.89 RIU−1 for MCF-7 in x polarization and 73.26 RIU−1 for MDA-MB-231 in y polarization. The proposed biosensor outperformed the existing literature. This biosensor offers significant potential for early stage breast cancer detection, contributing to more accurate and timely diagnoses, ultimately aiding in better treatment outcomes and patient survival.