Biosensor based on photonic crystal fiber and surface plasmon resonance for glucose, HIV, and cancer cells detection

This paper presents a high-sensitivity biosensor based on a Surface Plasmon Resonance (SPR) Photonic Crystal Fiber (PCF). Light is confined in a single mode within the core by a lattice of air holes, while the fiber surface is coated with a circular gold thin film to excite plasmonic waves. The sensing performance was evaluated through numerical simulations using the Finite Element Method (FEM) in COMSOL Multiphysics 6.3. The design was optimized by refining structural parameters, including the air hole diameter (d), lattice pitch (ᴧ), and gold layer thickness (tg), to maximize light-matter interaction and minimize confinement loss. The optimized device demonstrates superior wavelength sensitivity (S λ ) and amplitude sensitivity (S A ) across a diverse spectrum of biological analytes. For cervical cancer (HeLa) detection, the sensor achieves an S λ of 7,333 nm/RIU and a high amplitude sensitivity of 1,942.79 RIU −1 , representing a significant improvement over earlier reported value. Other malignancies are detected with high precision, including breast cancer (MDA-MB-231 and MCF-7) at 8,571 nm/RIU and 7,692 nm/RIU respectively, T-lymphocyte cancer (Jurkat) at 5,500 nm/RIU, and adrenal tumors (PC12) at 5,000 nm/RIU. Beyond cellular detection, the platform exhibits an outstanding sensitivity of 3,857 nm/RIU for HIV-infected blood and 4,000 nm/RIU for glucose solutions. Comprehensive numerical analysis across a refractive index range of 1.32 to 1.39 revealed a maximum sensitivity of 8,000 ± 452 nm/RIU and a peak Figure of Merit (FOM) of 291.7 ± 22.3 RIU −1 . With a peak detection resolution of 2.5 × 10 −6 RIU for biochemical sensing, this PCF-SPR platform offers a promising, cost-effective, and high-precision alternative to conventional diagnostic techniques such as surgical biopsies and chemical assays.