Lujan Center aids understanding of model membranes

December 13, 2011—Model membranes on solid supports have important applications for biophysical studies and novel biosensors. However, interactions between the solid support and membrane components could have a negative effect on the membrane’s architecture and physical properties.

A highly hydrated "cushion" between the membrane and the underlying support may alleviate these effects and enable research under more biologically relevant conditions. Jaroslaw Majewski of the Laboratory's Lujan Neutron Scattering Center and collaborators used neutron scattering to examine the structure of cushioned model membranes and to understand the factors controlling the structure. The journal Langmuir featured this research on its cover.

Tunable membranes

Scientists used the surface profile analysis reflectometer (SPEAR) at the Lujan Center for their studies of supported lipid bilayers containing polyethylene glycol (PEG) lipopolymer. The embedded lipopolymer provides a simple means for controlling the biomembrane architecture and its properties. When the lipopolymer has a reactive end group on which to bond (the support surface), distributed hydrated cushion architectures are obtained. This method creates full coverage membranes supported by laterally segregated, sub-micrometer cushions. A hydrated cushion is not formed when the lipopolymer does not have a reactive end group to bond with the support.

These systems are highly tunable and can yield different cushion architectures. For example, the membrane can be made to float on top of a well-anchored polymer cushion or rearranged to expose a polymer chain forest to the environment, or to create a hybrid system in which the membrane is decorated on both sides with the polymer chains. This structural information could promote understanding of the biophysical properties of membranes and optimization for desired applications.

Majewski; Chad Miller of Stanford Synchrotron Radiation Lightsource; Erik Watkins, Rita El-khouri, Brian Seaby, and Tonya Kuhl of University of California, Davis; and Carlos Marques of Université de Strasbourg, France performed the research.

DOE Office of Science funds the Lujan Center and the SPEAR reflectometer. The work supports LANL’s Global Security and Energy Security mission areas and the Materials for the Future science pillar.