Proc. Natl Acad. Sci. USA 115, 861–866 (2018)

Elasticity is key to a cell’s function and vitality, but measuring it requires non-invasive techniques that offer high spatial resolution, while being quick and flexible. Unfortunately, standard methods tend to be invasive or slow, or instead require unfavourable cell fixation. Measuring elastic waves propagating through cells might be one way of circumventing these issues. Shear waves, for example, are easily inducible and linked to elasticity by their propagation speed. Now, Guy Cloutier and co-workers have exploited these properties to devise a non-invasive method for rapid imaging of cell elasticity.

Cloutier and colleagues launched elastic shear waves in living cells held by pipettes, thus effectively inducing kilohertz ‘quakes’ in the cytoskeleton. They observed the sample through a standard optical microscope equipped with a high-speed camera and, using data analysis inspired by seismology, they obtained elasticity information about the cell — and even about its internal structures. With spatial resolution on the order of a few micrometres — and sub-millisecond temporal resolution — ‘cell quake elastography’ enables dynamic imaging of the mechanical properties of entire living cells in real time.