Pr. Bertrand Audoin
I2M, Département d’Acoustique Physique, UMR CNRS 5295, Université de Bordeaux
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Picosecond opto-acoustics microscopy to explore the intra-cell mechanics
Picosecond ultrasonics is an optical pump-probe technique where sub-ps light pulses are used for the remote generation and detection of coherent acoustic phonon in the GHz-THz frequency range. When coupled with convenient scanning devices and fast acquisition systems the technique offers several solutions for single cell microscopy. Image resolution can be better than standard optics and contrast comes from the endogenous mechanical properties of the cell. Another major feature of opto-acoustic microscopy is that it can probe the internal mechanical properties of organelles. For instance, the strong sensitivity of the technique to changes in mechanical properties measured inside the nucleus has made it possible to probe changes in the compaction of chromatin fibers, their flexibility or the formation of aggregates. It was thus possible to probe the supra-molecular intra-nuclear changes that accompany processes induced by chemical or physical means. Picosecond opto-acoustic microscopy is thus a breakthrough modality, which is providing new vistas on cell mechanics. Although not yet fully explored, its abilities to provide complementary insights into cell response to biological cues can currently be applied to various fundamental biological cellular processes.
