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Composition of supported model membranes determined by neutron reflection

Vacklin, H P; Tiberg, Fredrik LU ; Fragneto, G and Thomas, R K (2005) In Langmuir 21(7). p.2827-2837
Abstract
We have investigated the formation of supported bilayers by coadsorption of dipalmitoyl phosphatidylcholine (DPPC) with the nonionic surfactant P-D-dodecyl maltoside. The adsorption of mixed phospholipid-surfactant micelles on hydrophilic silica surfaces at 25 degrees C was followed as a function of bulk concentration by neutron reflection. Using chain-deuterated d(25)-beta-D-dodecyl maltoside and d(62)-DPPC, we demonstrate that it is possible to determine the composition of the bilayers at each stage of a sequential dilution process, which enriches the adsorbed layer in phospholipid and leads to complete elimination of the surfactant. The final supported bilayers have thicknesses of 51 +/- 3 angstrom and are stable to heating to 37... (More)
We have investigated the formation of supported bilayers by coadsorption of dipalmitoyl phosphatidylcholine (DPPC) with the nonionic surfactant P-D-dodecyl maltoside. The adsorption of mixed phospholipid-surfactant micelles on hydrophilic silica surfaces at 25 degrees C was followed as a function of bulk concentration by neutron reflection. Using chain-deuterated d(25)-beta-D-dodecyl maltoside and d(62)-DPPC, we demonstrate that it is possible to determine the composition of the bilayers at each stage of a sequential dilution process, which enriches the adsorbed layer in phospholipid and leads to complete elimination of the surfactant. The final supported bilayers have thicknesses of 51 +/- 3 angstrom and are stable to heating to 37 degrees C once all surfactant has been removed, and the structures agree well with other published data on DPPC supported bilayers. The coadsorption of cholesterol in a DPPC-surfactant mixture was also achieved, and the location and volume fraction of cholesterol in the DPPC bilayer was determined. Cholesterol is located in a 18 +/- 1 angstrom thick layer below the lipid headgroup region and leads to an increased bilayer thickness of 58 +/- 2 angstrom at 26 mol % of cholesterol. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
21
issue
7
pages
2827 - 2837
publisher
The American Chemical Society
external identifiers
  • scopus:16244379573
ISSN
0743-7463
DOI
10.1021/la047389e
language
English
LU publication?
yes
id
60a8c3c8-4778-4983-b717-2573bf164d03 (old id 157642)
date added to LUP
2007-07-12 13:31:10
date last changed
2017-10-01 03:38:51
@article{60a8c3c8-4778-4983-b717-2573bf164d03,
  abstract     = {We have investigated the formation of supported bilayers by coadsorption of dipalmitoyl phosphatidylcholine (DPPC) with the nonionic surfactant P-D-dodecyl maltoside. The adsorption of mixed phospholipid-surfactant micelles on hydrophilic silica surfaces at 25 degrees C was followed as a function of bulk concentration by neutron reflection. Using chain-deuterated d(25)-beta-D-dodecyl maltoside and d(62)-DPPC, we demonstrate that it is possible to determine the composition of the bilayers at each stage of a sequential dilution process, which enriches the adsorbed layer in phospholipid and leads to complete elimination of the surfactant. The final supported bilayers have thicknesses of 51 +/- 3 angstrom and are stable to heating to 37 degrees C once all surfactant has been removed, and the structures agree well with other published data on DPPC supported bilayers. The coadsorption of cholesterol in a DPPC-surfactant mixture was also achieved, and the location and volume fraction of cholesterol in the DPPC bilayer was determined. Cholesterol is located in a 18 +/- 1 angstrom thick layer below the lipid headgroup region and leads to an increased bilayer thickness of 58 +/- 2 angstrom at 26 mol % of cholesterol.},
  author       = {Vacklin, H P and Tiberg, Fredrik and Fragneto, G and Thomas, R K},
  issn         = {0743-7463},
  language     = {eng},
  number       = {7},
  pages        = {2827--2837},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Composition of supported model membranes determined by neutron reflection},
  url          = {http://dx.doi.org/10.1021/la047389e},
  volume       = {21},
  year         = {2005},
}