Invited Talk

Quantifying intracellular mechanics by active and passive measurements

Third Institute of Physics, Georg-August University of Göttingen, Göttingen, Germany

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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 through physical approaches have been largely driven by new methods that allow quantifying biological processes and constructing theoretical models with high predictive power. I will present our recent approaches that allow us to study active force generation and mobility in different cellular systems. Combining optical tweezer-based cell mechanics measurements with precise particle fluctuation analysis, we create a mechanical fingerprint [1] that allows separating of 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 into the system. We derive a new quantity, the mean back relaxation (MBR) which allows us to extract more information from confined trajectories than a classical MSD [2].