Dr Patricia Abellan

CNRS Researcher, Institute of Materials of Nantes (IMN) Jean Rouxel

Patricia Abellan is a CNRS researcher at the Institute of Materials of Nantes (IMN) Jean Rouxel since 2019. She received her BSc in Physics from the Aalborg University (Denmark) and her Ph.D. in Materials Sciences from the Autonomous University of Barcelona and Institute of Materials Science of Barcelona (ICMAB-CSIC), Spain, in 2011. She has held postdoctoral positions at the University of California – Davis and at the Pacific Northwest National Laboratory, USA, before taking a staff research scientist position at the SuperSTEM Laboratory (Daresbury, UK) in 2015. Her research focuses on the study of solid-liquid interfaces on hybrid and biomaterials using electron microscopy as well as on the elucidation of the radiation chemistry and radiation physics driving the processes at liquid-solid interfaces induced by the electron beam in an electron microscope. In 2013 she received the Best Ph.D. Thesis Award from the SME, in 2019 she was the laureate of the NExT Junior Talent program and in 2023 she won an European Research Council (ERC) Consolidator Grant.

Abstract: The Radiation Chemistry of vitrified frozen aqueous Interfaces in Cryogenic Electron Microscopy and Spectroscopy

Cryogenic transmission electron microscopy allows for the observation of samples in near native conditions and for higher electron beam tolerances than room temperature observations. Crucially, it provides the opportunity of obtaining quantified information from solid-liquid interfaces. In practice, accessing the solid-liquid interface at high-resolution represents specific challenges that are sample dependent and that must be addressed. A main limitation to many scanning (transmission) electron microscopy experiments at cryogenic temperatures, cryo-S(T)EM, is sample preparation. Also, these experiments are greatly affected by radiolysis caused by the imaging electron beam in the microscope. While the radiolysis of water by high-energy electrons has been extensively studied by conventional radiation chemistry methods, the radiolysis of water inside an electron microscope is still poorly understood.

Electron energy loss spectroscopy (EELS) can be performed inside the STEM, and thus, can allow for in situ analysis of radiation damage effects. In frozen hydrated aqueous specimens, cryo-EELS has already been used to study radiation damage.[1-3] Using new monochromated sources, with higher energy resolutions on the order of < 100 meV[4] and increased peak(signal)-to-background (S/B) ratio, new insights on the radiation damage of materials have been recently made possible. In this presentation, we will show that by using monochromated EELS at the oxygen K-edge and at cryogenic temperatures on thin films of ice, all radiolysis products (radicals and molecules) of water ice can be resolved (except for H₂ and •H)[5]. We will discuss the effect of different sample and microscope parameters as wel as the significance of our results with respect to the radiolysis of water ice and water ice interfaces. If times allows, we will also show our latest experimental results regarding our efforts to access hard-soft tissue interfaces within a bulk 3D volume. Indeed, for the case of hard-soft tissue interfaces in hydrated systems there are additional sample preparation and imaging challenges which arise by the mismatch between the bio(chemical), mechanical and physical properties of both sides of the interface.[6]