Regensburg 2010 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 9: Physics of Cells I
BP 9.9: Vortrag
Dienstag, 23. März 2010, 12:00–12:15, H43
Measuring cell mechanics and cell membrane properties by vertical pulling — •Schanila Nawaz1, Sai Li2, Mikael Simons1, and Iwan A.T. Schaap2 — 1Max Planck Institute for Experimental Medicine, 37077 Göttingen, Germany — 2III. Physkalisches Institut, Georg-August-Universität, 37077 Göttingen, Germany
Based on optical tweezers we have developed a portable (and affordable) trapping instrument that is able to work at the surface vicinity up to 50 μm away from the surface and can exert and measure vertical forces up to 0.1 nN. We have used our method to investigate the mechanical forces driving morphological changes during the development of myelin-forming cells. Such measurements heavily rely on the vertical pulling geometry because of the flatness of myelin cells (as thin as 50 nm). A trapped bead was automatically brought down to the cell and bead-cell contact was detected via a force feedback loop. The trapped bead was then pulled in vertical direction, away from the contact point. From the force-extension curves we can detect cell deformation, from which we can calculate the elastic response. At higher forces we pulled membrane tubes (tethers) out of the cell membrane. From the measured forces required to form these tethers we estimated the membrane tension in different stages of cell development.