Highly sensitive surface plasmon resonance sensor for refractive index detection of Helicobacter Pylori

Abstract

Helicobacter Pylori (H-Pylori) is gram-negative and spiral micro-organism that is responsible for its colonization in gastric microniche. The outcome of recent studies indicates that the development of H-Pylori in human bodies results in peptic ulcers, gastric mucosa, and gastric cancer. Therefore, on-time diagnosis of H-Pylori infection is very important to overcome its adverse effects. In this work, we have adopted the surface plasmon resonance (SPR) sensor for the detection of H-Pylori infection in human bodies. The SPR phenomenon is initiated by placing a 40–50 nm thick layer of gold nanoparticles on the flat surface of the glass prism. Four different configurations are designed by immobilizing a layer of biocompatible materials. Probe 1, 2, 3, and 4 are designed by immobilizing the layers of silicon oxynitride (SiON), molybdenum oxide (MoS2), graphene oxide (GO), and graphene, respectively. Added to this, the specificity of all the sensor structures is attained by functionalizing them with a 0.11 nm thick layer of urease enzyme, which oxidizes only in the presence of H-Pylori. Thereafter, the sensing analysis of all the sensor probes is done in a wide range of refractive index (RI) from 1.3227 to 1.3382 which corresponds to the RI of human urine in presence of H-Pylori. The performance analysis of the sensor is done in the terms of sensitivity, detection accuracy (DA), quality factor (QF), the figure of merit (FoM), and dip of a figure of Merit (DFoM). Added to this, the signal propagation through all the sensor structure is analyzed by using two-dimensional finite-difference-time-domain (FDTD) method-based tool.