Shear-induced membrane fusion in viscous solutions
Maxim Kogan1, Bobo Feng, Bengt Nordén
1Department of Chemical and Biological Engineering, Physical Chemistry, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 25, 2014
Summary
Shear forces in viscous solutions can induce lipid bilayer fusion in liposomes. This study demonstrates that mechanical stress, under specific conditions, can promote membrane fusion, a previously unreported phenomenon.
Area of Science:
- Biophysics
- Materials Science
- Physical Chemistry
Background:
- Large unilamellar vesicles typically deform or form pores under shear stress, rather than fusing.
- Membrane fusion solely induced by shear stress has not been previously documented.
Purpose of the Study:
- To investigate whether shear forces in a viscous medium can induce lipid bilayer fusion.
- To explore the conditions under which mechanical stress promotes liposome fusion.
Main Methods:
- Utilized Couette flow to apply controlled shear rates to liposome solutions.
- Varied solution viscosity using sucrose concentrations (0-50 wt %).
- Employed dynamic light scattering, Förster resonance energy transfer (FRET) assays, and linear dichroism (LD) spectroscopy to analyze liposome behavior and fusion.
Main Results:
- Observed fusion of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes at shear rates exceeding 3000 s(-1).
- Fusion occurred specifically in sufficiently viscous solutions (≥40 wt % sucrose).
- Demonstrated a correlation between mechanical-force-induced stress and lipid membrane fusion.
Conclusions:
- Mechanical shear stress in viscous solutions can induce lipid bilayer fusion.
- The findings support the hypothesis that lipid membranes can fuse in response to mechanical stress under specific conditions.
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