CC BY
9ALT'22
LD-I-20
LASER DIAGNOSTICS AND SPECTROSCOPY
Study of the molecular composition of cancer cells immobilized on SERS-active composite plasmonic nanostructures
1-Lomonosov Moscow State University, Physics Department, Leninskie Gory 1, 119991 Moscow, Russian Federation 2- Institute for Biological Instrumentation of Russian Academy of Sciences, 142290 Pushchino,
Moscow Region, Russian Federation Main author email address: osminkina@physics.msu.ru
Surface-enhanced Raman spectroscopy (SERS) is a promising technique for label-free detection and analysis of different molecules, which highly sensitive detection is possible due to the enhancement of electromagnetic fields created by the excitation of localized surface plasmons [1]. Such plasmons can be excited by the interaction of incident light with a metallic rough surface or nanoparticles. As a result, a significant increase in Raman scattering (usually by 104108) is observed when the analyzed object is on the nanostructured surface of plasmonic metals [2]. Currently, the SERS method has high sensitivity, excellent selectivity and non-destructive nature, so it is widely used for rapid detection of various chemicals, biomolecules and even living cancer cells [3-6].
In the present work, silicon nanowires (SiNWs) were obtained by electron beam lithography. The surface of the nanowires was decorated with gold nanoparticles (Au@SiNWs) to give them SERS-active properties. The structural properties of Au@SiNWs were examined using scanning (CarlZeiss SUPRA 40 FE-SEM) electron microscopy. MDA 231 human breast cancer cells were incubated on SiNWs and Au@SiNWs substrates for 24 hours and then fixed. To obtain microphotographs of cells on a fluorescence confocal microscope (laser excitation 405 nm), cell cytoplasm was stained with acridine orange (cytoplasm luminescence 520 nm), nuclei were stained with Hoechst 33341 (nuclear luminescence 460 nm), AuSiNWs were luminesced in the red spectral region at 630 nm. The molecular composition of cells immobilized on the obtained substrates was analyzed by Raman light scattering using a Confotec MR350 spectrometer.
According to the data obtained, there is a significant enhancement of the Raman signal from DNA, RNA, lipids, and proteins inside cells cultured on Au@SiNWs substrates compared to cells on SiNWs. Moreover, we have demonstrated that the position of the Au@SiNWs in the cell nucleus or cytoplasm can be clearly determined by measured SERS spectra. The nanowires literally pierce the cells, depending on scanning and fluorescence confocal microscopy. At the same time, the obtained Au@SiNWs are not toxic to the cells up to 4 days of incubation.
The substrates developed will help to approximate the understanding of bioprocesses and cellular functions on a molecular level, which could be crucial for progress in molecular cell biology, oncology, and pathology. This work was supported by the Russian Science Foundation (Grant No. 20-12-00297).
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L.A. Osminkina1,2
