Plasmonic Nanoparticle-based Protein Detection by Optical Shift of a Resonant Microcavity

TL;DR

This paper introduces a novel biosensing method that combines whispering gallery modes with plasmonic nanoparticles, achieving high sensitivity in protein detection through optical resonance shifts.

Contribution

It presents the first integration of WGM biosensing with metallic nanoparticle assays and provides a computational model explaining enhanced sensitivity.

Findings

Quantitative analysis of BSA protein binding to gold nanoparticles

Resonance frequency shifts align with a two-component adsorption model

Demonstrates improved detection sensitivity using plasmonic enhancement

Abstract

We demonstrated a biosensing approach which, for the first time, combines the high-sensitivity of whispering gallery modes (WGM) with a metallic nanoparticle based assay. We provided a computational model based on generalized Mie theory to explain the higher sensitivity of protein detection through Plasmonic enhancement. We quantitatively analyzed the binding of a model protein (i.e., BSA) to gold nanoparticles from high-Q WGM resonance frequency shifts, and fit the results to an adsorption isotherm, which agrees with the theoretical predictions of a two-component adsorption model.