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BP: Fachverband Biologische Physik

BP 30: Posters: Physics of Cells

BP 30.19: Poster

Thursday, March 17, 2011, 17:15–20:00, P3

Microrheology: A new algorithm for the conversion of mean squared displacement to dynamic shear moduli — •Tobias Paust¹, Anke Leitner¹, Michael Beil², and Othmar Marti¹ — ¹Institute of Experimental Physics, Ulm University — ²Department of Internal Medicine I, Ulm University

For describing the mechanical properties of a viscoelastic medium a possible way is to measure the thermal motion of a particle embedded in the medium and compute the unilateral transform.

The conversion of the mean squared displacement to the dynamic shear moduli is in the focus of interested in this work. We provide a new method for calculating the Laplace transform and therefore gather information about the mechanical properties of the sample. A superposition of well-defined analytical functions which are fitted to the measured data leads to the frequency-dependent storage and loss moduli of the system. In that way one can describe the viscoelastic behavior of the system in the needed frequency range without any approximation.

We show examples of mean squared displacements and the calculations of the elastic and diffusive part of different systems.