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Scanning X-Ray Nano-Diffraction on Eukaryotic Cells

Vendredi 20 septembre 2013 10:30 - Duree : 1 heure
Lieu : CTRM Control Room, ESRF - 6 Rue Jules Horowitz - Grenoble

Orateur : Britta WEINHAUSEN (Institute for X-Ray Physics, University of Göttingen, Germany)

Britta Weinhausen, Christian Dammann, Oliva Saldanha, Jens-Friedrich Nolting, Robin Wilke, Christian Olendrowitz, Tim Salditt, and Sarah Köster. The cytoskeleton of eukaryotic cells is a complex network of filamentous biopolymers, which gives cells their versatile shapes and specific mechanical properties. It mainly consists of three different types of filaments : actin filaments, microtubules and intermediate filaments. Keratin intermediate filaments mainly occur in epithelial cells, where they form about 100 nm thick bundles that are organized in a crosslinked network and provide these cells with a high tensile strength as well as the capability to withstand external stresses. Our goal is to probe the native structure of keratin bundles in living eukaryotic SK8/K18 cells in a physiological environment. For this purpose we use X-ray diffraction with a nano-focused X-ray beam, which enables us to achieve high-resolution structural information in combination with a non-destructive sample preparation. Nevertheless, to simplify the experimental set-up, first synchrotron experiments were performed on fixed and freeze-dried cells. High-resolution dark-field contrast images, where the cellular substructure is visible, were obtained and the analysis of single diffraction patterns obtained on the cell body showed oriented scattering corresponding to a high degree of orientation in the sample. As the next experimental step we developed a novel type of X-ray compatible microfluidic device, which is based on silicon nitride membranes as window material and allows for studies on hydrated biological samples. Scanning nano-diffraction experiments using hard X-rays were performed on fixed (hydrated) as well as living cells in these flow chambers at different synchrotron set-ups. Different contrast mechanisms were employed to generate real-space images of the cells with a resolution on the order of the beam size.

Contact : eva.jahn@esrf.fr

Discipline évènement : (Physique)
Entité organisatrice : (ESRF)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire ESRF)
Site de l'évènement : Polygone scientifique

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