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BP: Fachverband Biologische Physik

BP 22: Physics of Cells I

BP 22.8: Vortrag

Mittwoch, 16. März 2011, 17:15–17:30, ZEU 250

Cell-substrate impedance analysis of cellular motility — •Helmar Leonhardt, Matthias Gerhardt, and Carsten Beta — Institute of Physics and Astronomy, University of Potsdam, Germany

Electric cell-substrate impedance sensing (ECIS) measures the frequency dependent impedance of a small disc-shaped electrode to ac current in the presence of cells. Cells on the electrode restrict the current path, forcing it to pass through the gaps between neighboring cells or through the cell membranes. We have applied ECIS to motile cells of the social amoebae Dictyostelium discoideum. During starvation, Dictyostelium forms multicellular aggregates, which eventually turn into a migrating slug and later into a fruiting body to facilitate spore dispersal. The chemotactic motility of Dictyostelium cells requires the formation and retraction of pseudopodia, resulting in cyclic changes of cell shape and size, which lead to distinct periodicities in the impedance signal. Thus, while shape oscillations of single cells and small ensembles are often difficult to detect by optical microscopy, ECIS can serve as a biosensor for detection of spatiotemporal changes on the nanometer scale such as shape, size, junctional resistance, or cell-substrate separation.