Key points are not available for this paper at this time.
Brillouin spectroscopy uses the interaction of a laser light with picosecond timescale density fluctuations in the sample. It gives access to the mechanical properties (stiffness, viscosity…) on a sub-micrometer scale and at GHz frequencies. Since 2015, BLS has been successfully used for mechanical phenotyping and imaging with a contrast based on the stiffness in single cells using spectroscopic and time-resolved implementations, live organisms, plant tissues and teeth. Because it is label-free, all-optical and non-destructive, BLS has gained interest in the pharmaceutical and biomedical fields as a promising tool to investigate the mechanobiology of different pathologies. However, its relevance from a physiological standpoint remains debated due to the ultrashort timescales involved. Since the probing mechanism involves coupling of photons to longitudinal phonons, variations in the scattering spectra can be interpreted as the response of the sample to an infinitesimal uniaxial compression. With a few examples and some fundamental concepts, I will give some insights on how to interpret such data in biological samples, and offer new perspectives.
Dehoux et al. (Tue,) studied this question.