Gold Nanorod Assisted Enhanced Plasmonic Detection Scheme of COVID-19 SARS-CoV-2 Spike Protein

Abstract

The beautiful interplay between light and matter can give rise to many striking physical phenomena, surface plasmon resonance (SPR) being one of them. Plasmonic immunosensors monitor refractive index changes that occur as a result of specific ligand-analyte or antibody-antigen interactions taking place on the sensor surface. The coronavirus disease (COVID-19) pandemic has jeopardized the entire world and has resulted in economic slowdown of most countries. In this work, a model of a sandwich plasmonic biosensor that utilizes gold nanorods (Au NRs) for the detection of COVID-19 SARS-CoV-2 spike protein is presented. Simulation results for different prismatic configurations for the basic Kretschmann layout are presented. It is found that a BK7 glass prism-based SPR sensor has an incremental sensitivity of 111.11 deg RIU^-1. Additionally, using Comsol Multiphysics the electric field enhancement observed for various aspect ratios and layouts of Au NRs are discussed in depth.

Keywords: COVID‐19; gold nanorods; kretschmann layouts; plasmonic immunosensors.

Figure 1

Structure of the plasmonic immunoassay.

Figure 2

SPR reflectivity curve.

Figure 3

Variation of SPR angle and sensorgram response as a function of change in R.I. of the analyte for a) SF10, b) SF11, and c) BK7 prisms.

Figure 4

Evanescent decay of the electric field penetrating into the analyte solution from the surface of Au nanosheet along the central line of Au NR at the resonance condition for a) AR = 1 and b) AR = 4.

Figure 5

Normal electric field distributions at the resonance condition for Au NR with different aspect ratios and located at various distances from the Au nanosheet for AR = 1 a–e) and AR = 4 f–j).