Gold-Coated SPR-PCF Biosensor for Early-Stage Malaria Screening in the Human Body

This study introduces a Surface Plasmon Resonance (SPR) sensor based on a Photonic Crystal Fiber (PCF) aimed at the early screening of malaria in blood samples. The sensor is designed with a circular PCF structure that features hexagonally arranged air holes and a gold-coated exterior. It facilitates surface plasmon excitation at the metal-analyte interface. Performance evaluations of the sensor against normal and malaria-infected red blood cells (RBC) at various stages-ring, trophozoite, and schizont were conducted using numerical simulations through the Finite Element Method (FEM) in COMSOL Multiphysics v5.6, with each stage having unique refractive indices. The proposed sensor exhibits remarkable sensitivity and minimal confinement loss, achieving wavelength sensitivities of 12,857.143 nm/RIU, 7,083.33 nm/RIU, and 4,500 nm/RIU for the ring-stage, trophozoite-stage, and schizont-stage, respectively. The corresponding amplitude sensitivities are 1,741.95 RIU⁻¹, 1,518.886 RIU⁻¹ , and 766.734 RIU⁻¹ . The corresponding figure of merit (FOM) is calculated as 267.86, 202.38, and 128.57. Additionally, the sensor exhibits low confinement losses of 8.48 dB/cm for normal RBC, 4.79 dB/cm for ring-stage, 2.54 dB/cm for trophozoite-stage, and 1.66 dB/cm for schizont-stage infected RBC. These results underscore the sensor's potential for accurate, label-free malaria detection and offer a promising solution for portable, real-time diagnostic applications.