Brillouin Microscope

Mechanobiology is an emerging field that study the interaction between mechanical forces and cells behaviour. Standard techniques used to measure the mechanical properties of cells and tissues face significant limitations, they require contact forces, making them invasive or lack of appropriate subcellular resolution in 3D. 

Brillouin spectroscopy has been widely used in the context of material science to study material mechanical property such as elasticity and viscosity. Recently it has been translated to the study of biological systems as a powerful non-invasive new tool that allow 3D access to the sample. As a non-destructive technique, Brillouin works in a non-contact and label free manner, relying on the Brillouin light scattering (BLS) principle. BLS is an inelastic scattering in which light interacts with acoustic waves or density fluctuations that are intrinsically present in any medium or material due to thermal vibrations. Because of that interaction, the frequency of the scattered light undergoes a shift (Brillouin shift), in which its spectral line shape can lead to insights into the local viscoelastic properties of samples. The typical values of the frequency shifts for biological samples are on the order of GHz. 

Applying BLS to biological samples comes with several challenges, but in the last few years it has work successfully in many medical fields, from diagnostic to biomechanic. Elastic and viscous properties regulate several cell mechanisms, from proliferation to differentiation, in response of external environment.