PCF-SPR sensor with an external sensing system for the rapid detection of malaria in human blood

This research introduces a photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) sensor designed for rapid malaria detection by analyzing refractive index (RI) changes in red blood cells (RBCs). The sensor consists of a central core air-hole surrounded by two orthogonal rectangular rings, each containing six circular air holes. The dual-core, dual-side polished PCF-SPR sensor is placed next to the sensing channel containing malaria-affected RBCs. This external sensing design facilitates easier RBCs circulation and greater fabrication flexibility compared to internal sensing systems. Malaria-infected RBCs, which exhibit distinct RIs, induce measurable shifts in the SPR resonance wavelength (RW) and confinement loss. The sensor performance is analyzed for different malaria stages: ring, trophozoite, and schizont. Simulations using COMSOL Multiphysics and full-vector finite element method (FEM) reveal wavelength sensitivities (WS) of 5714, 4737, and 4138 nm/RIU; amplitude sensitivities (AS) of −630, −922, and −9511/RIU; signal-to-noise ratio (SNR) values of 1, 2, and 2.11; and limits of detection (LoD) of 26.67, 25.23, and 31.54 nm for the ring, trophozoite, and schizont phases, respectively. The design, featuring fewer air holes, enhances fabrication feasibility and detection accuracy. Overall, the proposed PCF-SPR sensor demonstrates high sensitivity, strong SNR, and low detection limits, making it a promising tool for rapid malaria diagnosis and improved patient care.