MonoLayer Graphene-Based Plasmonic Biosensor for Urine Glucose Detection

Abstract

In this proposed work, a plasmonic biosensor based on graphene has been presented to detect the biosample consisting of urine glucose. The proposed biosensor is comprised of five layers in the order of prism/Au/Si/graphene-sensing medium. P-polarized monochromatic light of 633 nm has been used for the excitation of the plasmons at the metal–semiconductor interface. This simulation study shows, by optimizing the thickness of gold (Au), silicon (Si), and graphene, the proposed biosensor can provide the sensitivity up to 219°/RIU (Refractive Index Unit) and gives the distinct shift in the resonance angle for a quite small variation in the value of refractive indices (1.335, 1.336, 1.337, 1.338, 1.341, 1.347) corresponding to the glucose concentration level in non-diabetic person (0–15 mg/dl) and diabetic person (0.625 gm/dL, 1.25 gm/dL, 2.5 gm/dL, 5 gm/dL, and 10 gm/dL), respectively. A comparison is also made with, a bare gold (Au) layer and combination of gold–silicon (Au–Si) layer-based structure, and it is found that monolayer graphene plays a major role and enhances the sensitivity remarkably better than the other two structures which are having a sensitivity of 150°/RIU and 180°/RIU, respectively. We expect this novel work, which would be helpful in the diagnosis of the sugar concentration level with high sensitivity and high accuracy.