Marie Paule Pileni is a pioneering force in nanotechnology, renowned for her groundbreaking and multidisciplinary research that has opened new frontiers in science. Her work focuses on nanocrystal self-assemblies into unique crystalline structures, revealing distinctive chemical and physical properties influenced by crystalline order, all while maintaining the intrinsic properties of the individual nanocrystals. In a recent breakthrough, Pileni demonstrated that these assemblies can form within tumours and persist even beyond cell death-a discovery patented in 2021, with promising implications for biomedicine. Pileni has authored over 450 scientific publications and holds the title of Grand Officer of the Legion of Honor.