TRANSMISSION ELECTRON MICROSCOPY LAB FOR NANO-IMAGING AND -ANALYTICS OF FUNCTIONAL SOLID STATE AND BIOLOGICAL MATERIALS

The core facility electron microscopy (EM) of the Paris Lodron University Salzburg comprises a scanning electron microscope (SEM) and a 200 kV cold field emission gun transmission electron microscope (TEM). It supports around 90 researchers and 70 PhD students in the field of material science, solid state chemistry, solid state physics, mineralogy, biology and medicine by providing compositional and structural analytics from micrometer to nanoscale resolution.
Within the last years, two trends emerged at the interdisciplinary intersection of electron microscopy, materials science and biological sciences, which are at the origin of this proposal. High-resolution imaging of biological structures, often under cryo-conditions, became a main focus of the biological EM community (Nobel prize for Cryo EM in 2017). Cryo-TEM facilitates the analysis of structures in their native environment in close-to-live conditions at the nanoscale without the influence of chemical fixatives used in conventional TEM. This allows the investigation of structure-function relationships in biological samples ranging from purified macromolecules, isolated cell compartments or organelles to extracellular vesicles, viruses, whole cells and tissue sections. These techniques resolve biological structures beyond the limit of light microscopy and are therefore enabling research of biological systems at the nanoscale ranging from molecular and cell biological processes in biomedical -, developmental - or environmental biology, to the development of pharmaceutical applications. Imaging techniques in this field are routinely carried out under beam damage control and low dose conditions.
In parallel, active materials became more important in materials science. Active materials are functional materials, which undergo or facilitate processes like energy storage, catalysis and energy conversion, one of the central challenges of today´s societies. Imaging their surface properties and their nanostructure is extremely important to understand their function. In contrast to other functional materials, they are often metastable. Analyzing active materials on the nanoscale needs beam damage control, similar to biological samples, and often an assessment of the electronic structure of the material on the nanoscale, since it is critical for a concise understanding of their function.
Therefore, there is an urgent need for high contrast imaging and electronic structure assessment on the nanoscale under low dose/cryo conditions for biological and material science samples in Salzburg, especially since these possibilities are missing in the west of Austria. Equipping the existing TEM with a cryo preparation and transfer unit, a cryo holder, an improved camera system and an energy filter (Modul 1) will enable the necessary progress in the field of biology and material science in Salzburg. Cryo conditions will enable the imaging of biological structures relevant for the cutting edge research in molecular biology, while the energy filter serves for contrast enhancement. In materials science, cryo conditions will help to reduce beam damage and the filter allows electron energy loss spectroscopy, which will provide insight into the redox chemistry and the electronic structure and possible light-induced electric field-enhancements of active materials and devices on the nanoscale. This strengthens the internationally competitive materials science community in Salzburg. In both fields, high impact publications and follow-up projects are expected in consequence to this investment. In the start-up phase (Module 2), standard operation procedures for cryo sample preparation and (high contrast) imaging of biological samples and for the assessment of electronic structures of active materials and devices will be developped. These processes are linked not only by using the same infrastructure but also by the common goal to inflict as little sample damage as possible.