Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 12: Posters: Imaging

BP 12.3: Poster

Dienstag, 1. April 2014, 09:30–12:30, P1

An insight into structural changes induced to cells by chemical fixatives using X-ray nano-diffraction — •Clémenet Hémonnot, Britta Weinhausen, Rita Graceffa, Robin Wilke, and Sarah Köster — Institute for X-Ray Physics, University of Göttingen, Germany

Various research methods have been developed to study the structure and composition of biological cells, the most prominent ones being fluorescence and electron microscopy. However, for most of these methods, sample preparation such as chemical or cryogenic fixation, staining or labeling, or tissue sectioning is prone to introduce artifacts. Thus, our aim was to use a label-free technique that probes cells in their native, aqueous environment at high resolution. We have applied X-ray nano-diffraction to image cells in microfluidic devices. High spatial resolution due to small wavelengths is combined with high penetration depth, enabling us to study entire cells. The microfluidic devices allow us to keep the cells alive as well as reducing the radiation damage by cooling the sample and by decreasing the concentration of free radicals through constant buffer or media flow. We have performed X-ray nano-diffraction experiments on fixed-hydrated and living eukaryotic cells. In particular, we have compared three widely employed chemical fixatives and analyzed the overall structure of the nucleus and cytoplasm. The different fixatives indeed introduce a different degree of structural changes on length scales on the order of 35 to 45 nm.