The substrate matters in the Raman spectroscopy analysis of cells

Abstract

Raman spectroscopy is a powerful analytical method that allows deposited and/or immobilized cells to be evaluated without complex sample preparation or labeling. However, a main limitation of Raman spectroscopy in cell analysis is the extremely weak Raman intensity that results in low signal to noise ratios. Therefore, it is important to seize any opportunity that increases the intensity of the Raman signal and to understand whether and how the signal enhancement changes with respect to the substrate used. Our experimental results show clear differences in the spectroscopic response from cells on different surfaces. This result is partly due to the difference in spatial distribution of electric field at the substrate/cell interface as shown by numerical simulations. We found that the substrate also changes the spatial location of maximum field enhancement around the cells. Moreover, beyond conventional flat surfaces, we introduce an efficient nanostructured silver substrate that largely enhances the Raman signal intensity from a single yeast cell. This work contributes to the field of vibrational spectroscopy analysis by providing a fresh look at the significance of the substrate for Raman investigations in cell research.

Gold nanostars for efficient in vitro and in vivo real-time SERS detection and drug delivery via plasmonic-tunable Raman/FTIR imaging

“…This represents a significant difference in terms of Raman spectroscopy due to the non-linear relation between Raman intensity and electric field. 35 As shown in Figure 3B These data prove that MTX-nanostars are optimal candidates for intracellular SERS detection and drug release using Raman/FTIR imaging and that behave as Raman scattering enhancers due to their tunable SPR and large number of hot spots on the surface associated sharp tips.…”

Identification of Individual Exosome-Like Vesicles by Surface Enhanced Raman Spectroscopy

“…[25,26] In this respect, different types of SERS-substrates have been developed to obtain plasmon enhancement and record Raman spectra from (sub)cellular components down to the single biomolecule level. [27] These can be, but are not limited to, well defined nanostructured surfaces of gold [28] or silver [29] and (intracellular) aggregated Ag [30] or AuNP [31] . Both Ag-nanograin coated chips and precipitated AuNP clusters were recently applied for bulk EV measurements.…”

Metal nanoparticles reveal the organization of single-walled carbon nanotubes in bundles

“…Here we used samples with electrochemically grown metal nanoparticles on SWCNT networks as a reference system since this approach excludes the inuence of additional solvents involved in the microuidic deposition. We relied on Ag nanoparticles in favour of Au as the protocol for electrochemical deposition of Ag particles is better established in our group 33 and both material systems show a signicant plasmonic response in the visible range. Fig.…”