Highly Sensitive Surface Plasmon Resonance Biosensors Utilizing Prism-Waveguide Configuration for Detection of Alzheimer Disease Biomarker

Alzheimer’s disease (AD) is a disease in cognitive regions in the human brain. Also the detection of AD in the early stage is too important. In this regard, a surface plasmon resonance (SPR) biosensor which comprises prism-silver/gold-SiO2 is proposed to detect of AD with high sensitivity. The properties of the AD sensor are numerically investigated with finite-difference time domain (FDTD) with different structural parameters. For this purpose, the effect of the incident beam waist, structural parameters, prism materials, and the temperature at 632 nm are then inspected to improve the structural parameters of the AD biosensor including the sensitivity and figure of merit (FOM). Our numerical calculations indicate that the proposed AD biosensor is able to operate with ultra-high sensitivity with maximum FOM of 31 and sensitivity of 1200 nm/refractive index unit (RIU) for small change of Δn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta n$$\end{document}= 0.4, in the refractive index of analyte. We believe that the proposed AD biosensor may be used as a potential platform for AD detection in earlier stages.