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DY: Fachverband Dynamik und Statistische Physik
DY 33: Statistical physics of biological systems I (joint session BP/DY)
DY 33.1: Vortrag
Mittwoch, 3. April 2019, 15:00–15:15, H4
Active noise fuels the heterogeneous anomalous diffusion of inert nanoparticles in the cytoplasm — •Adal Sabri1, Xinran Xu2, Diego Krapf2, and Matthias Weiss1 — 1Experimental Physics I, University of Bayreuth, Germany — 2School of Biomedical Engineering, Colorado State University, CO, USA
Diffusive motion of inert particles in the cytoplasm of living cells is generally assumed to be driven by thermal noise. This assumption appears particularly justified for the frequently observed sublinear growth of the particles' mean square displacement ('subdiffusion').
In order to probe quantitatively to which extent also active noise contributes to (sub)diffusional motion in living matter, we have introduced inert quantum dots into the cytoplasm of living cells and performed extensive single-particle tracking experiments in untreated cells and after disrupting the cytoskeleton. In all cases a pronounced subdiffusive motion of the particles with a distinct anti-correlation of successive steps was observed. Yet, the degree of the diffusion anomaly and the generalized diffusion coefficients showed marked changes when the integrity of the cytoskeleton was compromised, i.e. particles moved less vivid when cytoskeleton-associated active transport was erased. This observation highlights that cytoplasmic subdiffusion is partially fueled by active noise. In line with this notion, several measures of the trajectories, e.g. the gaussianity, highlight a strongly heterogeneous random walk with a temporally and/or spatially varying noisy driving.