Applied Science Graduate Group, Department of Biomedical Engineering, University of California Davis, 3001 Ghausi Hall, Davis, USA.
Published: September 2013
AI Article Synopsis
Article Abstract
We report the experimental observation of osmotically induced transient pearling instabilities in vesicular membranes. Giant phospholipid vesicles subjected to negative osmotic gradient, which drives the influx of water in to the vesicular interior, produces transient cylindrical protrusions. These protrusions exhibit a remarkable pearling intermediate, which facilitates their subsequent retraction. The pearling front propagates from the distal free end of the protrusion toward the vesicular source and accompanies gradual shortening of the protrusion via pearl-pearl coalescence. Real-time introduction of a positive osmotic gradient, on the other hand, drives vigorous shape fluctuations, which in turn produce cylindrical, prolate- and pear-shaped intermediates presumably due to an increased vesicular area relative to the encapsulated volume. These intermediates transiently produce a pearled state prior to their fission. In both cases, the transient pearling state gives rise to an array of stable spherical daughter vesicles, which may be connected to one another by fine tethers not resolved in our experiments. These results may have implications for self-reproduction in primitive, protein-free, cells.
Nanobioengineering Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 15-21, 08028 Barcelona, Spain. Department of Electronics and Biomedical Engineering, University of Barcelona, C/Martí i Franqués 1, 08028 Barcelona, Spain. Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Av. Monforte de Lemos, 3-5, 28029 Madrid, Spain. Author to whom any correspodence should be addressed. Current address: 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics of University of Minho, AvePark-Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco, Guimarães, Portugal.
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We report the experimental observation of osmotically induced transient pearling instabilities in vesicular membranes. Giant phospholipid vesicles subjected to negative osmotic gradient, which drives the influx of water in to the vesicular interior, produces transient cylindrical protrusions. These protrusions exhibit a remarkable pearling intermediate, which facilitates their subsequent retraction.
The ability of cells to undergo reversible shape changes is often crucial to their survival. For red blood cells (RBCs), irreversible alteration of the cell shape and flexibility often causes anemia. Here we show theoretically that RBCs may react irreversibly to mechanical perturbations because of tensile stress in their cytoskeleton.
