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Composite-scattering plasmonic nanoprobes for label-free, quantitative biomolecular sensing



Chi Zang, Debadrita Paria, Stephen Semancik, ishan Barman


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 a metal nanostructure. Here, we present a design of plasmonic nanostructures based on rationally structured metal-dielectric combinations, which we call composite scattering probes (CSP), to generate an integrated multi-modal biosensing platform featuring LSPR and surface-enhanced Raman scattering (SERS) measurements. Specifically, we propose CSP configurations that have several prominent resonance peaks enabling higher tunability and sensitivity for self-referenced multiplexed analyte sensing. Using electron-beam evaporation and thermal de-wetting, we have fabricated large area, uniform, and tunable CSP, which are suitable for label-free LSPR and SERS measurements. The CSP prototypes were 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 was demonstrated. Additionally, CSP facilitates complementary untargeted plasmon-enhanced Raman measurements from the sample's compositional contributors. With further refinement, we envision that our 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.


Raman spectroscop, refractive index, FEM, microfabrication, plasmonics


Zang, C. , Paria, D. , Semancik, S. and Barman, I. (2019), Composite-scattering plasmonic nanoprobes for label-free, quantitative biomolecular sensing, Small, [online], (Accessed April 15, 2024)
Created September 1, 2019, Updated March 7, 2024