Au-Al2O3-Coated Highly Sensitive Broad-Range Refractive Index Sensor for Detecting Malaria Disease in Human Blood

This article represents the photonic crystal fiber (PCF)-based surface plasmon resonance (SPR) biosensor for broad-range refractive index (RI) sensors along with the detection of malaria disease in the human body.
$\alpha $
-Al2O3-Au dielectric-metal interface has been proposed to stimulate the free electron on the metal surface via evanescent to result in an SPR phenomenon. The proposed sensor shows a sufficient shift in resonance wavelength for the change in external RI from 1.32 to 1.40 for an optimized Al2O3/Au thickness of 50/12 nm. The broad-range sensing applicability of the designed sensor shows a maximum sensitivity of 6000 nm/RIU when the external RI changes from 1.38 to 1.40. The detection accuracy (DA) of the designed sensor is reported to be
${1.66} \times {10}^{-{5}}$
(RIU) and reported compatible in comparison to broad RI sensors. The proposed SPR sensor has been utilized to sense the malaria diseases in the human body by filling infected RBC samples on the dielectric-metal surface. The proposed study aids in detecting various stages of malaria-infected RBCs, including the ring phase, trophozoite phase, and schizont phase, by measuring the shift in resonance wavelength. The sensor’s wavelength sensitivity varies across the phases: 5714.28 nm/RIU for the ring phase, 5263.15 nm/RIU for the trophozoite phase, and 5931 nm/RIU for the schizont phase. The sensor exhibits the highest reported sensitivity among other biological sensors in this category. The proposed sensor fulfills all the requirements for diagnosis of early malaria disease in the human body along with its high sensitivity, low detection limit, and capability of sensing broad RI.