A highly sensitive D-shaped PCF SPR biosensor for early malaria detection: Design and performance analysis

The rising incidence of malaria underscores the need for effective diagnostic tools for early detection. This work proposes a D-shaped photonic crystal fiber (PCF) biosensor that is based on the surface plasmon resonance (SPR) principle to increase biocompatibility and sensitivity in the early detection of malaria disease. There are three red blood cell (RBC) phases (ring, trophozoite, and schizont), when the RBCs are affected by malaria parasites. The proposed D-shaped biosensor is designed with three separate air-holes with different diameters. To get an optimized performance for detecting different RBC phases, the biosensor is coated with a 40 nm gold (Au) layer and a 15 nm titanium dioxide (TiO2) layer. An Au layer is deposited over the fused silica, followed by a 1 μm analyte layer. A 1.7 μm perfectly matched layer (PML) is then incorporated into the layer containing the analyte to consume scattered light. The biosensor's wavelength sensitivities (WS) are analyzed using finite element methods (FEM) and the maximum values obtained are 57,000.00, 36842.11, and 22,482.76 nm/RIU for the ring phase, trophozoite phase, and schizont phase, respectively. The highest amplitude sensitivities (AS) obtained are 150.10, 744.21, and 277.55 RIU−1 for the corresponding phases. The influence of the variations in Au layer thickness and air-hole diameter is also investigated. The proposed biosensor outperformed the existing literature for malaria detection. Due to its high sensitivity and simple design, this biosensor has great potential for the effective detection of biochemical and biological analytes.