Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 24: Cell Mechanics (in vivo)
BP 24.4: Vortrag
Donnerstag, 29. März 2007, 10:45–11:00, H44
High Resolution Mapping of Cell Mechanics (in Vivo) Using Digital Pulsed Force Mode — •Michael Holzwarth1, Alexander Gigler2, and Othmar Marti1 — 1Institute of Experimental Physics, Ulm University, D-89069 Ulm, Germany — 2Present address: Section Crystallography, University of Munich, Theresienstrasse 41/II, D-80333 Munich, Germany
Local mechanical properties of living cells have been investigated by means of AFM, using Digital Pulsed Force Mode (DPFM). The DPFM images the surface while probing its mechanical properties locally. At least one force curve is recorded for each point of the scanned area. Thus, more than 500,000 curves have been recorded and completely evaluated for each single experiment.
The glass-like substrate served as an online reference material for calibration purposes. First, the force trajectories were corrected for the viscous drag force in the liquid environment. Secondly, the curves within the region of the substrate were phase corrected to compensate for the time lag of the signal in the setup assuming a purely elastic response of the reference material. Finally, all the force traces have been corrected by using this calibration and evaluated according to common continuum-elastic models.
The resulting images allow the assignment of values of Young's modulus, local adhesion and hysteretic behaviour at a high lateral resolution all over the cell body. The procedure of our measurement and the corresponding signal correction strategy of the automated data evaluation will be shown.