Research project Unveiling dynamical heterogeneities using novel coherent x-ray sources

Dynamical heterogeneities (DyHes) emerge in liquids upon cooling, when molecules form regions with distinct slow and fast dynamics. Even though DyHes are ubiquitous across research fields, they have so far eluded direct experimental observation.
Unveiling dynamical heterogeneities using novel coherent x-ray sources

In water, simulations indicate that DyHes are largest around 220K. This temperature however depends on the model used and it has been difficult to measure experimentally pure liquid water dynamics in this temperature due to freezing. Interestingly, at the same temperature occurs the so-called protein ‘glass’ transition. Around this temperature many proteins lose their conformational flexibility and biological function. Is this transition due to the intrinsic temperature dependence of the protein motion or is it dictated by DyHes in the surrounding water molecules?
This project aims to unveil experimentally DyHes in prototype glass-formers, aqueous solutions and hydrated protein dynamics. The purpose is to resolve the long-lasting question related to the origin of the protein ‘glass’ transition, which will have major implications in understanding enzymatic activity and protein folding. The experiments utilize novel coherent x-ray diffraction techniques in new x-ray sources, such as the Swedish synchrotron MAX IV and the European X-ray Free-Electron Laser which are only recently available. As such, the long-term impact of the proposed investigations is to train scientists to use these new technologies.

Project managers

Foivos Perakis
Department of Physics

Unlocking Cryoprotection: The Role of Glycerol in Supercooled Water

Researchers uncover how glycerol, a common cryoprotectant, manipulates water's behavior at extremely low temperatures to prevent ice formation. The study, published in Nature Communications, provides a deeper understanding of the complex interplay between glycerol and water, with profound implications for cryopreservation – the science of preserving biological materials at ultra-low temperatures. This is an international research effort, led by Stockholm University (SU), in collaboration with Pohang University of Science and Technology (Republic of Korea), RIKEN SPring-8 Center (Japan) and Brooklyn College of the City University of New York (USA).

Department of Physics

Understanding proteins and water with physics

Anita Girelli is a new fellow in the Marie Skłodowska-Curie Actions program from the European Commission in 2024. Originally from Verona in Italy, Anita came to Fysikum in 2022 to start her first postdoc with Foivos Perakis. The way from Italy to Sweden was not always straight forward. For one, Anita took some time to fall in love with physics— I always liked math but at my first contact with physics, I thought it was weird and boring.

Department of Physics

Applying physics and chemistry problems in biological systems

Foivos Perakis was born and raised in Athens, Greece. Already at high school he was attracted to math, physics or computer science. During his studies at the Physics department at the University of Crete, he took the opportunity to study as an ERASMUS student at the University of Amsterdam. Later on, Foivos did his PhD in University of Zurich and a postdoc at Stanford. In 2016 he moved to Sweden as a researcher at Fysikum. He was appointed as an assistant professor in 2019 and a Wallenberg Fellow in 2023. His research group focuses on liquid-liquid transitions and proteins in crowded and cryogenic environments.

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