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BP: Fachverband Biologische Physik

BP 33: Cell adhesion, mechanics and migration I (joint BP/CPP)

BP 33.6: Vortrag

Mittwoch, 18. März 2015, 11:00–11:15, H 1058

Shape and adhesion dynamics of amoeboid cells studied by cell-substrate impedance fluctuations — •Helmar Leonhardt, Matthias Gerhardt, and Carsten Beta — Universität Potsdam, 14476 Potsdam OT Golm

We present electrical impedance measurements of single amoeboid cells on microelectrodes. Wild type cells and mutant strains are studied that differ in their cell- substrate adhesion strength. We recorded the projected cell area by time lapse microscopy and found a correlation between kinetics of the projected area (cell shape oscillation) and the impedance long-term trend. We developed a data processing routine to extract such trends. We furthermore observed that cell-substrate attachment strength strongly affects the impedance in that the magnitude of fluctuations are enhanced in cells that effectively transmit forces to the substrate. For example, in talA- cells, which lack the actin anchoring protein talin, the fluctuations are strongly reduced. Such short-term fluctuations are extracted by high-pass filtering the original data. Typically, amoeboid motility advances via a cycle of membrane protrusion, substrate adhesion, traction of the cell body and tail retraction. This motility cycle results in the quasi-periodic oscillations of the projected cell area and the impedance. In all cell lines measured, similar periods were observed for this cycle, despite the differences in attachment strength. Based on the approach presented here, we can separate the changes in the impedance signal that are caused by the projected cell area from the fluctuations induced by the cell-substrate adhesion.