Title: Direct visualization of flow-induced conformational transitions of single actin filaments in entangled solutions
Authors: Lettinga, Pavlik # ×
Issue Date: 9-Oct-2014
Series Title: Nature Communications vol:5
Article number: 5060
Abstract: While semi-flexible polymers and fibres are an important class of material due to their rich
mechanical properties, it remains unclear how these properties relate to the microscopic
conformation of the polymers. Actin filaments constitute an ideal model polymer system due
to their micron-sized length and relatively high stiffness that allow imaging at the single
filament level. Here we study the effect of entanglements on the conformational dynamics of
actin filaments in shear flow. We directly measure the full three-dimensional conformation of
single actin filaments, using confocal microscopy in combination with a counter-rotating
cone-plate shear cell. We show that initially entangled filaments form disentangled
orientationally ordered hairpins, confined in the flow-vorticity plane. In addition, shear flow
causes stretching and shear alignment of the hairpin tails, while the filament length
distribution remains unchanged. These observations explain the strain-softening and shearthinning
behaviour of entangled F-actin solutions, which aids the understanding of the flow
behaviour of complex fluids containing semi-flexible polymers.
ISSN: 2041-1723
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Soft Matter and Biophysics
× corresponding author
# (joint) last author

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