Towards digital transparency of biological tissues

Researchers at the Langevin Institute in Paris have proposed a computational matrix imaging method for making biological tissues transparent in optical microscopy. More specifically, this method aims at overcoming the aberration issues and multiple scattering phenomena that prevent conventional microscopes from imaging biological tissues in depth (i.e beyond a few hundred microns). While, in the past, adaptive focusing methods, inspired by astronomy, have been able to overcome low-order aberrations, these approaches are effective only over a few microns, deep in biological tissues. Here, from non-invasive reflection measurements, the authors manage to retrieve the transmission matrix that connects any point inside the tissues with each sensor of a camera outside. This matrix is the Holy Grail for imaging. It allows a fine compensation of all the aberrations that light undergoes during its travel through the medium. It also allows the filtering of the multiple scattering noise which generally strongly alters the contrast in optical microscopy. More broadly, our approach can be extended to any type of wave. Applications range from biomedical diagnosis in optical microscopy and ultrasound imaging to the detection of cracks in industrial materials. This project has received funding from the European Research Council (grant n° 610110 and 819261).

Figure: Imaging of a resolution target through a highly opaque monkey cornea. Matrix imaging (right) reveals details of the resolution target that were totally hidden by the edematous cornea in confocal microscopy (left) because of aberrations and multiple scattering.

A. Badon, V. Barolle, K. Irsch, A.C. Boccara, M. Fink, A. Aubry, « Distortion matrix concept for deep optical imaging in scattering media », Sci. Adv. 6, eaay7170, 2020