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Mechanical Behavior of a Supported Lipid Bilayer under External Shear Forces.

Jönsson, Peter LU ; Beech, Jason LU ; Tegenfeldt, Jonas LU and Höök, Fredrik LU (2009) In Langmuir 25(11). p.6279-6286
Abstract
Shear forces from a pressure-driven bulk flow in a microfluidic channel can be used to induce and control the motion of a supported lipid bilayer (SLB) formed on the walls of the channel. We here present a theoretical model that relates the experimentally observed drift velocities of an egg yolk phosphatidylcholine (egg PC) SLB to the hydrodynamic drag force from the bulk flow, the intermonolayer friction coefficient, b, of the bilayer, and the friction coefficient, b(ls), between the lower leaflet of the bilayer and the supporting substrate. The drift velocity and diffusivity of the lipids in the SLB were obtained by photobleaching a delimited area of fluorescently labeled lipids and subsequently monitoring the recovery and convective... (More)
Shear forces from a pressure-driven bulk flow in a microfluidic channel can be used to induce and control the motion of a supported lipid bilayer (SLB) formed on the walls of the channel. We here present a theoretical model that relates the experimentally observed drift velocities of an egg yolk phosphatidylcholine (egg PC) SLB to the hydrodynamic drag force from the bulk flow, the intermonolayer friction coefficient, b, of the bilayer, and the friction coefficient, b(ls), between the lower leaflet of the bilayer and the supporting substrate. The drift velocity and diffusivity of the lipids in the SLB were obtained by photobleaching a delimited area of fluorescently labeled lipids and subsequently monitoring the recovery and convective motion of the bleached spot. A striking observation was that the drift velocity of the lipids was observed to be nearly 6 orders of magnitude smaller than the bulk velocity at the center of the channel. This predicts a value for b(ls) that is at least 25 times as high as predicted by the traditional model with the SLB and the support spaced by a homogeneous 1 nm thick film of water. In addition, the intermonolayer friction coefficient was estimated to 2 x 10(7) Pa s/m, a value that increased after addition of glycerol to the bulk solution. This increase was accompanied by an equal decrease in the lipid diffusivity, with both observations indicating an increased viscous drag within the bilayer when glycerol was added to the bulk solution. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
25
issue
11
pages
6279 - 6286
publisher
The American Chemical Society
external identifiers
  • wos:000266604000040
  • pmid:19408897
  • scopus:66749117763
ISSN
0743-7463
DOI
10.1021/la8042268
language
English
LU publication?
yes
id
d5fe7152-5c56-4d8d-9224-9daad314f883 (old id 1412790)
date added to LUP
2009-06-11 12:37:55
date last changed
2017-06-11 03:31:47
@article{d5fe7152-5c56-4d8d-9224-9daad314f883,
  abstract     = {Shear forces from a pressure-driven bulk flow in a microfluidic channel can be used to induce and control the motion of a supported lipid bilayer (SLB) formed on the walls of the channel. We here present a theoretical model that relates the experimentally observed drift velocities of an egg yolk phosphatidylcholine (egg PC) SLB to the hydrodynamic drag force from the bulk flow, the intermonolayer friction coefficient, b, of the bilayer, and the friction coefficient, b(ls), between the lower leaflet of the bilayer and the supporting substrate. The drift velocity and diffusivity of the lipids in the SLB were obtained by photobleaching a delimited area of fluorescently labeled lipids and subsequently monitoring the recovery and convective motion of the bleached spot. A striking observation was that the drift velocity of the lipids was observed to be nearly 6 orders of magnitude smaller than the bulk velocity at the center of the channel. This predicts a value for b(ls) that is at least 25 times as high as predicted by the traditional model with the SLB and the support spaced by a homogeneous 1 nm thick film of water. In addition, the intermonolayer friction coefficient was estimated to 2 x 10(7) Pa s/m, a value that increased after addition of glycerol to the bulk solution. This increase was accompanied by an equal decrease in the lipid diffusivity, with both observations indicating an increased viscous drag within the bilayer when glycerol was added to the bulk solution.},
  author       = {Jönsson, Peter and Beech, Jason and Tegenfeldt, Jonas and Höök, Fredrik},
  issn         = {0743-7463},
  language     = {eng},
  number       = {11},
  pages        = {6279--6286},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Mechanical Behavior of a Supported Lipid Bilayer under External Shear Forces.},
  url          = {http://dx.doi.org/10.1021/la8042268},
  volume       = {25},
  year         = {2009},
}