6th Annual Symposium
Physics of Cancer
September 7-9, 2015
|PoC - Physics of Cancer - Annual Symposium|
Characterising single chain motion in a crowded environment
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The thermal motion of polymer chains in a crowded environment is anisotropic and highly confined. Whereas theoretical and experimental progress has been made, typically only indirect evidence of polymer dynamics is obtained either from scattering or mechanical response. Towards a complete understanding of the complicated polymer dynamics in crowded media such as biological cells, it is of great importance to unravel the role of heterogeneity and molecular individualism.
Here, we employ extremely stiff synthetic polymers and demonstrate the confined motion of a single chain using time-resolved fluorescence microscopy. This is the first comprehensive study in which we observe the crossover from the Rouse to the reptation regime and quantify the relevant length scales and time constants of polymer dynamics in crowded environments in one experiment at the single chain level confirming de Gennes-Edwards-Doi theory [1-3]. Within our approach, by carefully analyzing the space- and time-dependence of the dynamics of the polymer chains, we have probed the local homogeneity/heterogeneity of the polymer matrix. This local probe technique will allow extracting the same parameters in highly heterogeneous samples that are inaccessible for bulk techniques, especially crowded cytoskeletons in the cell, as a function of the stage of the cell cycle and response to stress.