One-dimensional photonic crystal biosensors encompassing defect layer for bloodstream bacteria detection

Photonic crystal biosensors have become essential tools for accurately detecting and analyzing analytes with high sensitivity and specificity. As a result, they have gained immense value in a variety of fields including medical diagnostics, environmental monitoring, and food safety. To enhance their scalability, cost-effectiveness, simple design, and tunable fabrication, it is necessary to explore novel fabrication techniques and material selection. Therefore, in this study, we theoretically investigated the sensing performance of a one-dimensional photonic crystal biosensor (1D PCB) for effective bloodstream bacteria (bacterium) detection. Specifically, the impact of varying type, thickness, and number of dielectric layers and Bragg surface on 1D PCB sensitivity (S), quality factor (QF), and detection accuracy (DA) were examined employing the transfer matrix method (TMM). The result indicate that, addition of dielectric layers enhances the overall band structure of the biosensor. On the other hand, increasing the thickness of the Bragg surface minimizes the sensing depth, thus improving the sensor’s performance. Notably, incorporation of six layers of dielectric layer, with Titanium dioxide (TiO \(_2\) ${}_2$ ) Bragg surface, and filling the defect layer with contaminated blood resulted in the maximum sensitivity of 509 nm/RIU, DA of 90%, and 51 RIU \(^{-1}\) ${}^{-1}$ QF. With its high sensitivity, ease of modeling, and cost-effective materials used, the proposed 1D PCB is an ideal candidate for biomedical applications.