Surface-enhanced spatially offset resonance Raman spectroscopy (SESORRS) contrast agents: the chemistry of gold nanostars

Nanostar SERS intensity is influenced by plasmonic changes induced by dye and biological environment

Abstract Text:

Gold nanostars (AuNStars) are promising substrates for biomedical surface-enhanced Raman scattering (SERS) applications and have found use as contrast agents for delineating tumor margins.¹ The sharp tips of AuNStars create regions of large electric field enhancements, making them particularly attractive for applications where signal strength is paramount, such as surface-enhanced spatially offset resonance Raman spectroscopy (SESORRS), which retrieves spectral signals from nanoparticles buried deep within tissues.² Like all nanoparticles, stability is a key challenge in their biological application. However, the sharp tips of anisotropic plasmonic nanomaterials such as AuNStars present an additional stabilization challenge due to their high surface energy and inherent reactivity.³ This presentation will explore how the choice of Raman reporter molecule and the biological environment influence the plasmonic properties and SERS signal strength of silica-coated AuNStars. The results will be interpreted within the framework of SESORRS imaging by assessing how various biologically relevant conditions influence the ability to retrieve spectral signals from AuNStars embedded at depth within tissue. Characterizing the optical stability of plasmonic contrast agents in different biological environments that nanoparticles could encounter between injection and tumor localization is key for the clinical translation of SESORRS where strong and reproducible signals are required for accurate tumor margin delineation.

References:

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(2)         Nicolson, F.; F. Kircher, M.; Stone, N.; Matousek, P. Spatially Offset Raman Spectroscopy for Biomedical Applications. Chem. Soc. Rev. 2021, 50 (1), 556–568. https://doi.org/10.1039/D0CS00855A.

(3)         Sajanlal, P. R.; Sreeprasad ,Theruvakkattil S.; Samal ,Akshaya K.; and Pradeep, T. Anisotropic Nanomaterials: Structure, Growth, Assembly, and Functions. Nano Rev. 2011, 2 (1), 5883. https://doi.org/10.3402/nano.v2i0.5883.