Numerical investigation on copper based SPR biosensors for blood hemoglobin (Hb) detection

Abstract

This research investigates the application of a surface plasmon resonance (SPR)-based biosensor for detecting hemoglobin concentration in blood, utilizing different Kretschmann configurations. Hemoglobin, a crucial protein in red blood cells, serves as a biomarker for various medical conditions. It's concentration directly influences blood refractive index, a parameter detectable by SPR biosensors. While gold and silver are the most commonly used metals for SPR biosensors, this paper explores the use of different metals and semiconductors as alternatives to the traditional metals used in the Kretschmann configuration. Specifically, the performance of Germanium, Gallium Arsenide, Aluminum, and Copper as SPR layers was examined and compared. To evaluate material performance, an angle sweep of the incident light source was performed to analyze the sensitivity of the SPR angle to variations in the refractive index. The finite-difference time-domain (FDTD) method was employed for simulations, focusing on three key parameters: sensitivity, full width at half maximum (FWHM), and quality factor, to evaluate detection accuracy. The study found that copper is a highly effective replacement for silver and gold in hemoglobin detection as it exhibits high sensitivity ranging from approximately 190 to 255 deg/RIU and FWHM of 0.81 to 2.03. These findings offer valuable insights into the development of SPR-based biosensors for medical diagnostics.