Composite‐Scattering Plasmonic Nanoprobes for Label‐Free, Quantitative Biomolecular Sensing

Abstract

Biosensing based on localized surface plasmon resonance (LSPR) relies on concentrating light to a nanometeric spot and leads to a highly enhanced electromagnetic field near the metal nanostructure. Here, a design of plasmonic nanostructures based on rationally structured metal–dielectric combinations is presented, called composite scattering probes (CSPs), to generate an integrated multimodal biosensing platform featuring LSPR and surface‐enhanced Raman spectroscopy (SERS). Specifically, CSP configurations are proposed, which have several prominent resonance peaks enabling higher tunability and sensitivity for self‐referenced multiplexed analyte sensing. Using electron‐beam evaporation and thermal dewetting, large‐area, uniform, and tunable CSPs are fabricated, which are suitable for label‐free LSPR and SERS measurements. The CSP prototypes are used to demonstrate refractive index sensing and molecular analysis using albumin as a model analyte. By using partial least squares on recorded absorption profiles, differentiation of subtle changes in refractive index (as low as 0.001) in the CSP milieu is demonstrated. Additionally, CSPs facilitate complementary untargeted plasmon‐enhanced Raman measurements from the sample's compositional contributors. With further refinement, it is envisioned that the method may lead to a sensitive, versatile, and tunable platform for quantitative concentration determination and molecular fingerprinting, particularly where limited a priori information of the sample is available.

Optical Properties and Applications of Plasmonic‐Metal Nanoparticles

“…The light‐matter interaction (based on plasmonic NPs) can confine the detection range to an ultra‐thin layer near the surface of the particle to provide a local supersensitive lab‐on‐a‐chip device working at a very low concentration of analytes. [ 81 ]…”

Towards rational design and optimization of near-field enhancement and spectral tunability of hybrid core-shell plasmonic nanoprobes

“…the shell and the core), which is not visible in a dimer composed of solid nanoparticles. This shows promise as the basis of a multi resonance system with different degree of tunability of individual peak for multiplexed measurements 53 . Our calculations reveal that the maximum NE is greater than 10 5 and can enable SERS enhancements in the range of 10 11 (where the enhancement factor for SERS measurements is given by the 4 th power of the enhancement of the electric field amplitude) - which represents the maximum theoretical limit for plasmon-enhanced Raman scattering 36 .…”

Assembling Nano–Microarchitecture for Electromagnetic Absorbers and Smart Devices

“…They enable connecting the world together, with unexpected surprising convenience ( Figure ). [ 1–35 ] In recent years, 3D nano–micro architectures are emerging. At the same time, new technologies, new effects, new mechanisms, new materials, and new structures are bringing limitless vitalities to smart devices, and driving them towards integration, diversification, miniaturization, high performance, precision, and so on.…”