Theoretical investigation of diabetic urine detection by surface plasmon resonance sensor

Abstract EN

Methods of sensing glucose concentration in blood and other human fluids are rely upon various physical phenomena.

Nowadays, these methods have a great concern through many researchers.

Surface Plasmon Resonance (SPR), which is an important biosensing method, is an optical detection process that happens when a polarized light hits a prism covered by a thin metal layer.

Under certain conditions (wavelength, polarization and incidence angle) free electrons at the surface of the metal absorb incident light photons and convert them into surface plasmon waves.

A dip in reflectivity of the light is seen under these SPR conditions.

In this study, a mathematical model of Surface Plasmon Resonance (SPR) with kretschmann configuration investigated to increase the sensitivity for urine glucose concentration in the range 10-3000 mg/dL.

The numerical computation of this model rely on three-layer Fresnel equation with p-polarization.

Noble metals, naming Ag, Au, and Cu, that are known for their strong SPR at optical frequencies 430–770 THz, with a wide range of their thicknesses (1-71 nm) were selected as plasmonic metal in the proposed sensor to get high sensitivities.

The reflected SPR spectra, response curve, and sensitivity variation with thicknesses for these metals were computed by MATLAB program.

The maximum sensitivity was 163.77 o/RIU (degree/refractive index unit) for Au with thickness 41 nm.

Additionally Cu, with corresponding thickness 51 nm, which has proper sensitivity, might use as a non-invasive and low cost sensor which has drawback of oxidizing and corrosion..