High-speed Raman imaging of cellular processes

Abstract

Raman scattering microscopy provides information about the distribution and chemical state of molecules in live cells without any labeling or modification. In recent years, the imaging speed of Raman microscopy has improved greatly owing to the development of instruments that can perform parallel acquisition of Raman spectra from multiple points. In this article, we review recent advances in high-speed hyperspectral Raman imaging and its application to observe various biological processes such as cell mitosis, apoptosis and cell differentiation. Furthermore, we discuss the recent progress in Raman tags for the specific observation of bioactive small molecules in complex biological systems, including the development of organelle-specific probes, imaging of lipid rafts in an artificial monolayer membrane and application as a structure-sensitive tag.

Altered Adipogenesis in Zebrafish Larvae Following High Fat Diet and Chemical Exposure Is Visualised by Stimulated Raman Scattering Microscopy

“…The additional benefit of SRS imaging combined with semi-automatic adipocyte counting and volume computation has been demonstrated in this work. Compared with conventional Raman microscopy, the imaging rate of SRS can be orders of magnitude higher, but for only one vibrational band at the time [53,54]. SRS in principle is a quantitative method, but quantification of adipocyte content was not possible in these experiments due to the fixation with paraformaldehyde which adds to the SRS signal.…”

Raman Imaging in Cell Membranes, Lipid-Rich Organelles, and Lipid Bilayers

“…However, most of the alkyne structures that can be multiplexed over two colors have overlapping peaks. In 2014, Min and coworkers reported that by replacing 12 C in the simplest alkyne (C≡C) with one 13 C or two 13 C through isotope replacement, alkyne tags with three distinct signals at 2048, 2077 and 2125 cm -1 could be easily resolved [142]. As a proof of concept for multiplexing, lipids, DNA and RNA were successfully mapped in a single HeLa cell with minimum cross talk among the detection channels.…”

“…The spontaneous Raman signal is generally considered to be weak (1 photon in every 10 6 to 10 8 scattered photons), which has limited imaging speeds and utility for measuring the fast dynamics of the cell membrane. Various approaches have been developed over the years to increase the imaging speed, which were recently reviewed [13]. Herein, the recent developments Instrumentation for Raman imaging is not discussed here, and the reader is directed to appropriate reviews on the topic [14][15][16].…”

Vibrational Spectroscopy for Imaging Single Microbial Cells in Complex Biological Samples

“…For a more detailed introduction to this technique (as well as infrared spectroscopy), the reader is referred to Skoog et al (2007) and Lu et al (2011). Recent advances in the design of high-speed Raman imaging instrumentation have been summarized by Ando et al (2016). Moreover, developments concerning techniques including surface- and tip-enhanced Raman scattering (SERS and TERS), as well as resonance Raman and coherent anti-Stokes Raman spectroscopy (CARS), are discussed in several reviews (Opilik et al, 2013; Camp and Cicerone, 2015; Cicerone, 2016; Kano et al, 2016).…”

“…While a limited number of studies have been published on Raman imaging of microbial strains or uncultured cells within their native environments, new instrumentation is likely to lead to an expansion of this field by enabling reduced spectral acquisition times without a loss of signal intensity (Opilik et al, 2013; Ando et al, 2016; Kano et al, 2016). In addition, combining this approach with well-established methods in microbial ecology (including fluorescence in situ hybridization) (Wang et al, 2016) as well as newer techniques such as bioorthogonal chemical imaging (Berry et al, 2015; Wei et al, 2016) and Raman microfluidics (Chrimes et al, 2013) are likely to find increasing use in the analysis of microbiological samples.…”