Subcellular measurements of mechanical and chemical properties using dual Raman-Brillouin microspectroscopy

Abstract

Brillouin microspectroscopy is a powerful technique for noninvasive optical imaging. In particular, Brillouin microspectroscopy uniquely allows assessing a sample's mechanical properties with microscopic spatial resolution. Recent advances in background-free Brillouin microspectroscopy make it possible to image scattering samples without substantial degradation of the data quality. However, measurements at the cellular- and subcellular-level have never been performed to date due to the limited signal strength. In this report, by adopting our recently optimized VIPA-based Brillouin spectrometer, we probed the microscopic viscoelasticity of individual red blood cells. These measurements were supplemented by chemically specific measurements using Raman microspectroscopy.

Label‐free multi‐parametric imaging of single cells: dual picosecond optoacoustic microscopy

“…However, experimental techniques developed over the years generally require contact or the insertion of a local probe into the cell under study, which can cause significant under‐ or overestimation of the cell elasticity, as a result of complicated and inevitable linkages between the probe and the cell. Brillouin light scattering (BLS) micro‐spectroscopy offers an all‐optical route for noncontact, noninvasive and label‐free imaging of intracellular viscoelasticity and is now attracting growing attention in biomedical research and applications . However, BLS spectroscopy relies on the detection of spontaneous Brillouin scattering arising from weak incoherent thermal phonons, only one in every approximately 10 10 –10 12 photons contributes to the detected signal.…”

Optical assessment of changes in mechanical and chemical properties of adipose tissue in diet‐induced obese rats

“…Brillouin elastography (also known as Brillouin spectroscopy), an emerging spectroscopic technique, [11,12] is capable of assessing the elasticity for biomedical applications on the level of tissue [13–15] and individual cells. [16,17]…”

“…[19,20] Raman spectroscopy can be combined with Brillouin elastography for simultaneous measurements. [17,21–23] Raman spectroscopy is based on inelastic scattering that occurs due to specific molecular vibrations in the molecule of interest. The scattered photon exhibits a frequency shift compared to the frequency of the incident photon.…”

“…The Brillouin and Raman spectral measurements can be recorded simultaneously from the same position on the sample to provide complimentary assessment of the sample’s mechanical properties and chemical composition. [17,23]…”

Flow cytometry using Brillouin imaging and sensing via time-resolved optical (BISTRO) measurements

“…A linear correlation between the ISBS and spontaneous Brillouin spectra is clearly evident, indicating that the measured ISBS signal originated from the ultrasonic phonons within the sample. Our recent study shows that the Brillouin shift different between different RBC types is ~ 400 MHz 48 . According the correlation shown in Fig.…”