A Numerical Analysis of Rectangular Open Channel Embedded TiO₂-Au-MXene Employed PCF Biosensor for Brain Tumor Diagnosis

Abstract

In this work, a surface plasmon resonance (SPR) plasmonic photonic crystal fiber (PCF) biosensor embedded with a rectangular open channel (ROC) is proposed, enabling precise detection and discrimination between healthy and tumorous brain tissues. Healthy and tumorous tissues are considered liquid tissues, each possessing its own distinctive refractive index (RI). The ROC is coated with gold (Au) to generate surface plasmons. To facilitate ample biomolecules, a thin Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Tx-MXene layer is functionalized over gold. A thin TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer is coated on the ROC surface to strongly hold the Au nanoparticles, ensuring improved sensing performance. Healthy, cancerous, and tumor tissue samples exhibit unique resonance wavelengths, allowing for their diagnosis through the measurement of shifts in their respective resonance wavelengths. The essential performance parameters, including sensitivity (S), full width at half maximum (FWHM), and figure of merit (FoM) are evaluated. The computed sensitivities for normal and abnormal tissues <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i.e</i> ., gray matter, cerebrospinal fluid and oligodendroglioma are 12352.94 nm/RIU, 2030.45 nm/RIU, and 672.26 nm/RIU, measured with respect to white matter and the wall of a solid brain. And, for tumorous tissues (cancers and tumors) such as glioblastoma, lymphoma and metastasis, the sensitivities are 800 nm/RIU, 774.9 nm/RIU, and 643.26 nm/RIU, measured with respect to low grade glioma (Benign). Additionally, the proposed biosensor’s resolution (R) ranges from 1.25 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> to 8.09 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> RIU along with the maximum FoM of 126.05 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . Hence, this biosensor is poised to excel in the detection of tumor and cancer tissues, making it a promising candidate for advancing medical diagnostics.