Biomedical applications of the picosecond opto-acoustic microscopy.
Résumé
Picosecond optoacoustic microscopy is a technique that allows imaging single cells with an in-plane resolution limited by optics and with the mechanical properties as the contrast mechanism.[1,2] In this talk, the basic principles involved in single cell picosecond ultrasonics will be briefly reminded, and the large variety of physical parameters that can be extracted from a single signal will be illustrated. Using a pulsed opto-acoustic microscope we produce notably high-resolution images of the stiffness and adhesion of single migrating cells. The technique is also capable to image cell 3D morphology with an out-of-plane accuracy down to a tenth of the optical wavelength.[3] This capability will be illustrated with the measurement of the 3D morphology of an entire osteosarcoma cell. The mapping complies with the image obtained by standard atomic force microscopy for the same cell, and both reveal very close roughness mean values. These results open perspectives for the morphological phenotyping of cancer cells. This opto-acoustic modality was inserted on a regular upright microscope, making it handy to cooperate with the built-in bright field and with fluorescence microscopies.