Non-universal tracer diffusion in crowded media of non-inert obstacles
- We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer–obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer–obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physicalWe study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer–obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer–obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer–crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.…
Author details: | Surya K. Ghosh, Andrey G. CherstvyORCiDGND, Ralf MetzlerORCiDGND |
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URN: | urn:nbn:de:kobv:517-opus4-77128 |
Publication series (Volume number): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (186) |
Publisher: | The Royal Society of Chemistry |
Place of publishing: | Cambridge |
Publication type: | Postprint |
Language: | English |
Date of first publication: | 2014/11/26 |
Publication year: | 2014 |
Publishing institution: | Universität Potsdam |
Release date: | 2015/05/22 |
Tag: | anomalous diffusion; brownian-motion; escence correlation spectroscopy; excluded volume; infection pathway; langevin equation; living cells; physiological consequences; random-walks; single-particle tracking |
Number of pages: | 12 |
First page: | 1847 |
Last Page: | 1858 |
Source: | Phys. Chem. Chem. Phys., 2015,17, 1847-1858. - DOI: 10.1039/C4CP03599B |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access |
License (English): | Creative Commons - Namensnennung 3.0 Unported |
External remark: | Bibliographieeintrag der Originalveröffentlichung/Quelle |