Regensburg 2025 – scientific programme
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BP: Fachverband Biologische Physik
BP 17: Poster Session II
BP 17.39: Poster
Tuesday, March 18, 2025, 18:00–20:30, P4
Passively Measuring Cell Activity via Mean Back Relaxation — •Sarah Louisa Lädke1, Till Moritz Münker1, Julian Schulz1, Gabriel Knotz2, Matthias Krüger2, and Timo Betz1 — 1Third Institute of Physics, Georg-August-Universität Göttingen — 2Institute of Theoretical Physics, Georg-August-Universität Göttingen
While many statistical methods are available for the characterization of passive motion in thermodynamic equilibrium, the investigation of active motion in living systems remains a significant challenge. In particular, the study of intracellular mechanical properties requires techniques such as active microrheology to quantify the response of tracer particles to forces exerted via optical or magnetic tweezers. However, these methods often involve expensive and complex equipment, and their invasive nature can alter cellular behavior.
To address these limitations, we present an alternative approach to study intracellular mechanical properties and activity that relies only on passive measurements. To this end, we combine darkfield microscopy, highspeed imaging and image post-processing techniques to obtain trajectories of microparticles in Hela cells with nanometer and 300 microseconds spatial and temporal resolution. To filter noise that occurs in our particle tracking, we developed a new, Bayesian approach that can reliably differentiate between noise peaks and intrinsic fluctuations found in the frequency spectrum. Using the novel observable Mean Back Relaxation (MBR), we can link the particle tracks to intracellular activity and their mechanical properties.
Keywords: Non-equilibrium physics; Mean Back Relaxation; Image processing; Intracellular mechanical properties