Developing an ultra-sensitive biosensor utilizing one-dimensional photonic crystal for anemia diagnosis

Reliable and prompt detection methods are necessary due to widespread occurrence of anemia, particularly among children and pregnant women. Presented herein is a biosensor design utilizing a one-dimensional photonic crystal (1D PhC) with a defect, aimed at detecting anemia at various stages. Revealing refractive index modulation, the cavity, which is formed by the defect layer, responds to the blood sample derived from an individual suffering from anemia. Leveraging the principle of creating a narrow passband within the photonic band gap (PBG), this biosensor design is formulated. Silicon (Si) and silicon dioxide (SiO₂) are selected as the materials for the 1D PhC. Extensive analysis of sensor parameters is conducted to assess sensor efficacy, including sensitivity variation with changes in defect layer thickness in the PhC. The proposed biosensor demonstrates versatility, enabling detection across the spectrum of anemia severity, from mild to severe cases, with maximum detection limit of the order of 10^–6 refractive index units (RIU) and a maximum sensitivity of 421 nm/RIU.