The biennial KNCV-Van Arkel prize 2020-2021 is awarded to Dr. Karina Nakashima, for her PhD work at Radboud University Nijmegen. She was selected among several strong candidates. They performed excellent scientific research on a wide range of topics including fuel-propelled motion of colloidal particles, self-assembly of polyelectrolytes, and rheology of polymers. Dr. Nakashima described her own work in an inspiring thesis titled ‘Chemistry of active coacervate droplets’.
The central theme of the thesis is that of coacervate droplets as a model for prebiotic cells. Coacervate droplets are formed through liquid-liquid phase separation of aqueous polymer solutions. These droplets are typically several micrometers in diameter and can, for instance, be rich in proteins and nucleic acids. Coacervate-like droplets have been found inside present-day biological cells, which suggests that also in the prebiotic time period, they were able to bring together the molecules of life. This theme forms the common thread of the thesis, and it also determines its story-like overall structure.
Dr. Nakashima developed a network of chemical reactions whose relative rates give control over the reversible formation, growth, and dissolution of coacervate droplets. She also demonstrated that such actively growing droplets can maintain a stable size, without Ostwald ripening or merging of droplets, contrary to expectation for such surfactant-free systems. These results give important new insights into the physical chemistry underlying complex coacervation. In the words of one of her thesis supervisors, Dr. Evan Spruijt, it “puts coacervate droplets in a completely new and promising light as possible ancestors to modern cells”. The thesis exhibits Dr. Nakashima’s original and creative thinking, her outstanding talent as a chemical scientist, and her far-reaching insights into the problems of her field of research.
The Soft Matter section of the Royal Netherlands Chemical Society congratulates Dr. Nakashima with the Van Arkel award. May it inspire her and other physical chemists to continue to strive for excellence in their scientific research.