Elucidating Sensitivity and Stability Relationship of Gold–Carbon Hybrid LSPR Sensors Using Principal Component Analysis

Abstract

Sensitive localized surface plasmon resonance (LSPR) sensing is achieved using nanostructured geometries of noble metals which typically have dimensions less than 100 nm. Among the plethora of geometries and materials, the spherical geometries of gold (Au) are widely used to develop sensitive bio/chemical sensors due to ease of manufacturing and biofunctionlization. One major limitation of spherical-shaped geometries of Au, used for LSPR sensing, is their low refractive index (RI) sensitivity which is commonly addressed by adding another material to the Au nanostructures. However, the process of addition of new material on Au nanostructures, while retaining the LSPR of Au, often comes with a trade-off which is associated with the instability of the developed composite, especially in harsh chemical environments. Addressing this challenge, we develop a Au-graphene-layered hybrid (Au-G) with high stability (studied up to 2 weeks here) and enhanced RI sensitivity (a maximum of 180.1 nm/RIU) for generic LSPR sensing applications using spherical Au nanostructures in harsh chemical environments, involving organic solvents. Additionally, by virtue of principal component analysis, we correlate stability and sensitivity of the developed system. The relationship suggests that the shelf life of the material is proportional to its sensitivity, while the stability of the sensor during the measurement in liquid environment decreases when the sensitivity of the material is increased. Though we uncover this relationship for the LSPR sensor, it remains evasive to explore similar relationships within other optical and electrochemical transduction techniques. Therefore, our work serves as a benchmark report in understanding/establishing new correlations between sensing parameters.

Multilayer Nano-Structure for Enhanced Sensitivity of Surface Plasmon Resonance Biosensor

“…Selecting the appropriate metal layer for the surface is essential to optimize the sensor. Gold is commonly used as a sensor surface coating due to its high chemical stability [30][31][32], however, the gold coated SPR sensor is somewhat expensive. Another viable material for SPR sensors is silver, which has also demonstrated exceptional sensitivity.…”

Refractive Index-Modulated LSPR Sensing in 20–120 nm Gold and Silver Nanoparticles: A Simulation Study

“…Refractive index (RI) based Localized Surface Plasmon Resonance (LSPR) biosensing is a powerful label-free tool in the field of biosensing research. [1][2][3] This technique utilizes the changes in RI caused by the binding of molecules to the surface of noble metallic nanostructures, which in turn affects the LSPR peak wavelength and total absorbance of light by the nanostructures. 4 Fundamentally, when light interacts with the LSPR nanoparticles, it creates a collective oscillation of the conduction electrons on the surface of the nanoparticles.…”