Gold nanoparticles modified with aromatic alkynes for surface-enhanced Raman scattering bioimaging

Abstract

Surface-enhanced Raman scattering (SERS) is based on the plasmonic properties of noble metal nanoparticles, due to which they are able to amplify the Raman signal of adsorbed molecules. The Raman spectra can be an important information source when studying the cells and tissues. For these reasons, bioinert gold nanoparticles in combination with Raman reporters have been studied for decades for their potential applications in bioimaging and cell biology.
Imaging specificity is critical to accurate cellular studies. In this regard, the use of alkyne compounds as Raman reporters is of particular interest, since the target signal of triple bond stretching vibration appears in the so-called “silent region” (1800-2800 cm-1), in which there are no spectral overlaps from natural biological components. A limiting factor for the wider implementation of alkyne-targeted Raman imaging is that C≡C band appears in the SERS spectra only for a limited number of compounds. So, a search for the best gold nanoparticle – alkyne combinations is ongoing.
In this work, 17 aromatic alkynes were examined in combination with gold nanorods. Based on the spectral screening, 4-aminotolane was selected as a leading compound. Its conjugates with gold nanoparticles were synthesized using dithiobis(succinimidylpropionate) linker. These samples provide a 5-fold increase in intensity for the target signal of triple bond in comparison with electrostatically adsorbed 4-aminotolan. The obtained conjugates didn’t show cytotoxicity and demonstrated successful penetration into the cells.
This work was supported by Russian Science Foundation, grant № 22-73-10052. The authors would like to thank the Research Park of SPbU.

Speaker

Demenshin Andrey Igorevich
Saint-Petersburg State University
Russian Federation

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