Surface-Enhanced Raman Scattering and Cell Imaging Ability of Plasmonic Tags Based on Covalent Conjugates of Gold Nanorods With Aromatic Alkynes

The inherent benefits of Raman spectroscopy make it a suitable tool for the analysis of complex biological objects. Detection and imaging of mammalian cells is one of its development areas. Plasmonic tags endowed with alkyne reporter intended for bioimaging by surface-enhanced Raman scattering in the silent region are presented. Gold nanorods with covalently conjugated 4-aminotolane were obtained using dithiobis (succinimidyl propionate) and characterized by UV–Vis absorbance, transmission electron microscopy, and dynamic light scattering. Verification of surface amide bonds formation was performed with attenuated total reflectance and X-ray photoelectron spectroscopy. Surface-enhanced Raman scattering spectra of the tags were registered in various media and compared with a feedback from the similar system obtained through non-specific adsorption of 4-aminotolane on gold nanorods. Cytotoxicity of Raman reporter itself and its conjugates with gold nanorods were verified on HeLa cell line. Spectral mapping and scanning electron microscopy revealed the localized intracellular accumulation of the tags. The challenge associated with reduced imaging area due to formation of the tags aggregates inside the cells is pointed out.