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Nothing but noise? Quantifying intracellular mechanics from fluctuations.

hosted by Ulrich Schwarz

  04:00 PM
  Seminar Room 41 & online


Timo Betz is a biophysicist who is trying to understand how biological systems use physics in general, and mechanics in particular to perform their fascinating function. After studying physics in Würzburg and Austin, Texas, he obtained a PhD at the University of Leipzig investigating the mechanical properties of growing neurons. During his Postdoc and first group leader phase at the Institut Curie in Paris, he developed new tools to quantify active forces and cell mechanics in single cells and model tumor tissue. After returning back to Germany, he first obtained a Professorship in Münster, and recently moved to Göttingen. Currently he studies not only intracellular mechanics, but also how single cells can generate the forces to shape tissue in the context of muscle, cancer and even development.


Many biological systems rely on fundamental physical principles for their proper function. A key example are mechanical processes such as force generation and adaptation of stiffness and viscosity that have been instrumental to explain complex biomedical questions with physical concepts. Such advances in understanding cell biology by physical approaches have been largely driven by new methods that allow to quantify biological processes and to construct theoretical models with high predictive power. I will present our recent approaches that allow to study active force generation and mobility in different cellular systems. Combining optical tweezer based cell mechanics measurements with precise particle fluctuation analysis, we demonstrate a tuning of intracellular mechanics during cell division. Using the same tools, we can furthermore define a mechanical fingerprint that allows to separate different cell types based on their intracellular active mechanics. While these approaches still require a high precision optical tweezer measurement, a new approach can yield the same information using a simple passive observation. Here we exploit the Onsager principle to extract the non-equilibrium energy that is injected in the system. We derive a new quantity, the mean back relaxation (MBR) which allow to extract more information from confined trajectories than a classical MSD.