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| Invited Talk, Thursday, 17:30 – 18:00 |
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| Investigation of cellular
mechanics by atomic force microscopy
Meenakshi Prabhune1, Jens Schäpe2,
Ketaki Apte2, Maik Baumann1, Reimer Stick2,
Manfred
Radmacher1
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1
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Institute of Biophysics, University
Bremen, Otto-Hahn Allee, 28334 Bremen, Germany |
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2
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Institut of Cell Biology, University
Bremen, Leobener Straße NW2 A3290, 28359 Bremen, Germany |
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| Contact:
| Website |
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Atomic force microscopy (AFM) can be used to investigate biological samples
under physiological conditions and hence allows following the dynamics
of biological processes, in particular in living cells. In addition, the
application of forces allows elucidating the mechanical properties, i.e.
the local elastic moduli, of samples under investigation like cells or
polymeric films. The AFM can also be used to measure forces, which we have
used for determining the protrusion force of migrating cells.
Of special interest is the investigation of the mechanics during cellular
dynamics, e.g. cell division or migration. In eukaryotic cells the mechanical
properties are mainly determined by the cytoskeleton and thus mechanical
data reflect in most cases the status of the actin network. Changes in
architecture or composition of the cytoskeleton, or in the activity of
actin binding proteins, for instance of myosin creating tension in the
network, can be picked up by mechanical measurements.
Another focus of recent work is to determine mechanical cues as a function
of disease state of cells. We examined here two systems: cell nuclei and
cancer cells. (1) Some laminopathies, diseases that are related to the
lamin layer of cell nuclei, have been associated with differences in the
lamin layer. By expressing mutant lamins in the nucleus of Xenopus oocytes
and in fibroblast cells we are able to investigate mechanical reasons of
several laminopathies, which has been hypothesized. (2) Cancer cells are
thought to be much softer than normal cells, possibly due to different
migration or adhesion properties or because of differences in expression
levels of certain proteins. However, it is difficult to quantify this difference
in mechanics unambiguously since cancerous and normal cells, especially
when obtained from patients, exhibit many differences, e.g. in terms of
morphology. We have therefore compared two cell lines, which are well characterized
in their degree of malignity (or the absence of it for the control cells)
and are virtually indistinguishable in terms of morphology, degree of adhesion
and so forth.
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