Nanoscale Aggregation of Cellular β₂-Adrenergic Receptors Measured by Plasmonic Interactions of Functionalized Nanoparticles

Abstract

Adrenergic signaling that controls the contraction of cardiac myocyte cells and the beating of the mammalian heart is initiated by ligand binding to adrenergic receptors contained in nanoscale multiprotein complexes at the cellular membrane. Here we demonstrate that the surface-enhanced Raman scattering (SERS) of functionalized silver nanoparticles can be used to report on the receptor aggregation state of specifically label beta(2)-adrenergic receptors on mouse cardiac myocyte cells. Furthermore, multimodal imaging including Raman, Rayleigh scattering, scanning electron microscopy, and luminescence imaging was combined to fully characterize the beta(2)-adrenergic receptor-mediated aggregation of silver nanoparticles on the membrane of cardiac myocytes. Scanning electron microscopy analysis reveals distinct SERS active clusters of between 10 and 70 nanoparticles per signaling domain from ultra-high-resolution images of beta(2)-adrenergic receptor clusters on the cellular membrane. These techniques can be generally applied to study the aggregation of other cell surface receptors and explore their distribution on cell surfaces.

Highly selective and sensitive surface enhanced Raman scattering nanosensors for detection of hydrogen peroxide in living cells

“…Especially, SERS signals of the Raman reporter molecule vary depending on the concentrations of the target inorganic species, which is the ideal criterion to determine the target inorganic species. For example, mobile and biocompatible pH nanosensors have been designed by modifying 4-mercaptobenzoic acid on gold nanoaggregates (Kneipp et al, 2007;Kennedy et al, 2009). Redox potential SERS nanosensors have been developed by decorating a noble-metal nanoshell with redox-responsive small molecules (Auchinvole et al, 2012;Thomson et al, 2015).…”

Development of nanoparticle probes for multiplex SERS imaging of cell surface proteins

“…Among the many factors that effect the observed Raman enhancement, proximity of the marker in question to the particle surface is one of them. 15 We chose a simple scaffold where functionalized mercaptomethylbenzene derivatives were used as chemically distinct Raman reporters. We have previously published the synthesis of (mercaptomethyl)benzonitrile and on its use as a Raman reporter on Ag NPs to probe cell surface receptors.…”

“…We have previously published the synthesis of (mercaptomethyl)benzonitrile and on its use as a Raman reporter on Ag NPs to probe cell surface receptors. 15 Here we prepared three analogous compounds with unique Raman sensitive functional groups. The NPs require additional ligands in order to target and stabilize them in aqueous media; however, the reporter molecules synthesized from benzene derivatives (which have higher scattering cross-sections) generate strong SERS spectra.…”

Surface-Enhanced Raman and Resonant Rayleigh Scatterings From Adsorbate Saturated Nanoparticles

“…Lastly, increasing use of the MMBN molecule in SERS imaging applications in our other recent work prompted us to fully characterize its SERS behavior in this correlation study. 15 MMBN can be coordinated onto an Au surface through the terminal thiol moiety. Its attachment to Au also reduces the repulsive surface charge resulting in the mild aggregation of colloidal sols that is necessary for sustaining a strong SERS response.…”