Document Type : Research

Authors

• Robabeh Talebzadeh ¹
• Shabnam Andalibi Miandoab ²

¹ Associate Professor, Department of Physics, Ta C, Islamic Azad University, Tabriz, Iran.

² Associate Professor, Department of Electrical Engineering, Ta C, Islamic Azad University, Tabriz, Iran.

Abstract

This study presents the design and theoretical analysis of a novel optical biosensor for the detection of malignant brain tissues. The proposed sensor is based on a one-dimensional photonic crystal structure (comprising alternating layers of silica and air) that incorporates a central defect cavity coated with a high-temperature superconducting nanocomposite based on bismuth (BSCCO). Using the transfer matrix method, we numerically investigated the transmittance spectrum of the structure. Our findings demonstrate that the introduction of the superconducting nanocomposite significantly enhances the interaction between incident electromagnetic waves and the biological samples, leading to the formation of distinct, sharp resonant modes within the photonic band gap. The spectral position of these resonant modes is highly sensitive to the refractive index of the analyte filling the cavity, which can be tuned by optimizing structural parameters such as the nanocomposite filling factor and the thickness of the sample cavity. By analyzing the transmittance spectra for various brain tissue types, including cerebrospinal fluid (CSF), low-grade glioma, medulloblastoma, glioblastoma, and lymphoma, we confirmed that each tissue type yields a unique and clearly distinguishable resonant peak. Our optimized design achieves a high sensitivity, for example reaching approximately 1.63 µm/RIU for the detection of lymphoma. This work demonstrates that the proposed 1D photonic crystal biosensor, incorporating bismuth-based high-temperature superconductors, offers a promising, highly sensitive, and label-free platform for the early and precise diagnosis of brain tumors. The simplicity of its 1D structure also makes it a cost-effective and practical candidate for developing advanced point-of-care diagnostic devices.

Keywords

• Biosensor
• Brain Tissue
• Nanocomposite
• Sensitivity
• Superconductor
• Photonic Crystal