Exploiting Plasmonics in Biosensing and Bioimaging: Monitoring CellReceptors with Surface Enhanced Spectroscopy and Microscopy

摘要

The plasmon resonance of noble metal nanoparticles (NP) manifests itself in a variety of extraordinary optical properties. Resonant excitation of the conduction electrons by incident radiation generates a localized surface plasmon resonance (LSPR) that is responsible for a variety of surface enhanced optical phenomena. This unique optical property coupled with well-established surface chemistry allows us to utilize both Ag and Au NP as optical contrasting agents to probe and monitor the surface receptors of cells. We have employed two plasmon-assisted optical techniques (namely, surface enhanced Raman scattering, and resonant Rayleigh scattering) to monitor the adrenergic receptors in mammalian cardiomyocyte cells that have been labeled with functionalized Ag NPs. In this study, a unique Raman reporter molecule, 4-(mercaptomethyl)benzonitrile, was developed to provide an easily identifiable vibration, the C≡N stretch, in a spectral window free from Raman bands of cell constituents and other biomolecules used in receptor crosslinking and surface passivation. Successfully labeled cells were then monitored with both optical techniques. Both techniques are related through the plasmonic properties of the noble metal NP and combined with high resolution imaging techniques; we outline the importance that different NP architectures play in the different imaging techniques. Furthermore, we will discuss the instrumentation and plasmonic implications in the design of NP best suited for such multimodal imaging approaches.