title: On the Mobility of Macromolecules in Cells
creator: Guigas, Gernot
subject: ddc-530
subject: 530 Physics
description: In the first part of this thesis diffusion measurements with fluorescence correlation spectroscopy on fluorescence-labeled nanogold particles in the cytoplasm and the nucleus of living cells are presented. The nanoparticles were detected to move by subdiffusion, i.e. their mean square displacement displayed a power-law scaling ~ t^a, a < 1. This observation can be explained with the high amounts of macromolecules (such as proteins) dissolved in intracellular fluids which obstruct the motion of indiviual nanoparticles. From the diffusion behaviour of the particles the complex shear modulus G(w) ~ w^a of the intracellular fluids was calculated, which showed the cellular interior to be viscoelastic on the nanoscale. Furthermore, the efficiency of a subdiffusive molecule to approach a fixed target was quantified. Computer simulations highlighted here that the probability to reach a target is increased for a subdiffusive particle as compared to a normal diffusive particle, which suggests that a cell may benefit from the subdiffusion of macromolecules in its interior. In the second part of the thesis the two-dimensional diffusion of cylindrical objects embedded in lipid membranes is investigated. Coarse-grained molecular dynamic simulations ('dissipative particle dynamics') demonstrated that the size-dependence of the diffusion coefficients is properly described by the Saffman-Delbrück theory.  
date: 2008
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/8583/1/Dissertation_Gernot_Guigas.pdf
identifier: DOI:10.11588/heidok.00008583
identifier: urn:nbn:de:bsz:16-opus-85830
identifier:   Guigas, Gernot  (2008) On the Mobility of Macromolecules in Cells.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/8583/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng