Nobel Prize in physics in 2018 and professor emeritus at the École polytechnique, Gérard Mourou is a scientist that nothing can stop. After revolutionizing ophthalmic surgery with the invention of a new laser technique, the physicist launched a challenging scientific project, which only a researchers of this fame could imagine: the transmutation of radioactive waste by high-power laser. Andra met him to find out more.

It is on the plateau of Saclay, south of Paris, that we meet Gérard Mourou. Here at École Polytechnique, the Nobel Prize in Physics has been working in his laboratory for many years. His enthusiasm remains intact when it comes to addressing the issue of lasers. His research on the subject represents the project of a lifetime. “For a long time, the power of lasers was limited, due to the risk of destroying them. Alongside Donna Strickland, with whom I share the Nobel Prize, we invented the technique of CPA (Chirped Pulse Amplification): the laser emits an ultrashort pulse that we will stretch a colossal factor before amplifying it. Thanks to the CPA one can produce considerable power, to the order of the petawatt (10e15W), without destroying the laser. This represents the equivalent of a hundred times the world electricity grid, ” explains Gérard Mourou.

For the physicist, this new invention opens perspectives in several areas, starting with ophthalmic surgery. An application that came to light as a result of an unlikely combination of circumstances: One of my students was aligning the laser for an experiment when it got the pulse in the eye. We went to the hospital where an intern found that the damage to the retina was absolutely perfect. This laser was the cleanest knife possible…

Adult cells in our body can only give rise to the same cell type. For example, a skin cell cannot give rise to a muscle cell but to skin cells only. This limits the potential use of adult cells for therapy. During early development, however, the cells in the embryo have the capacity to generate all cell types of our body, including stem cells. This capacity, which is called totipotency, has served as an inspiration for researchers to find new ways to recapitulate totipotency through cellular reprogramming in the lab.

Totipotent cells have their own speed

Totipotent cells have many properties, but we do not know all of them yet. Researchers at Helmholtz Munich have now made a new discovery: “We found out that in totipotent cells, the mother cells of stem cells, DNA replication occurs at a different pace compared to other more differentiated cells. It is much slower than in any other cell type we studied,” says Tsunetoshi Nakatani, first-author of the new study.