Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 17: Posters: Physics of Cells

BP 17.40: Poster

Wednesday, March 28, 2012, 17:30–19:30, Poster A

Impact of Temperature on Cell Nuclei Integrity in the Optical Stretcher — •Enrico Warmt, Tobias Kießling, Anatol Fritsch, Roland Stange, and Josef Käs — University of Leipzig, Faculty of Physics and Earth Sciences, Institute of Experimental Physics I, Soft Matter Physics Division, Linnéstraße 5, 04103, Leipzig, Germany

The deformation of cells in Optical Stretcher experiments is considered to be caused exclusively by the deformation of the cellular cytoskeleton. However, the visual appearance of certain cell types during the stretching process implicates events taking place in the cell organelles, especially the cell nucleus. To obtain a more detailed view into the cell we dyed the nucleus in different cell lines and stretched many cells to examine the behavior of the nucleus. At a certain laser power, we observe an abrupt restructuring of the nucleus of MCF-7 cells. This restructuring is irreversible and does not occur during a second stretch of the same cell. Interestingly, the intensity of the restructuring differs between cell lines in a highly reproducible way: While MCF-7 and HMEC show a significant restructuring, less or even no restructuring is observed on MDA-MB-231, MDA-MB-436 and MCF-10A cells. By controlling the ambient temperature, we show that restructuring is triggered by a laser-induced increase in temperature during measurement. The underlying physical processes and the origin of the variations among cell lines has to be clarified.