College Park, Maryland      June 6 - 10 , 2004

WP51: Structural Studies of Single Bilayer Lipid Membranes on a Patterned Surface

G.S. Smith (HFIR Center for Neutron Scattering, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.), S.M. Baker (Harvey Mudd College, Dept. of Chemistry, Claremont, CA 91711), J. Tan (Harvey Mudd College, Dept. of Chemistry, Claremont, CA 91711; Columbia University, Applied Physics and Applied Mathematics Dept., New York, NY 10027-8351), T. McQueen (Harvey Mudd College, Dept. of Chemistry, Claremont, CA 91711), J. Majewski (Los Alamos Neutron Science Center, Los Alamos National Laboratory)

One of the mechanisms by which proteins transport materials across living cell membranes is by forming pores in the lipid bilayer surrounding the cell. The pores consist of aggregates of protein molecules which form tubular structures which span the membrane. The transport through one of these pores may either be active, requiring an energy production reaction like the hydrolysis of ATP, or passive, where the molecule diffuses in the thermodynamically favorable direction. One clear requirement for the insertion and activation of the pores is a free membrane where the proteins can protrude from each surface. In this paper, we examine the utility of using templated surfaces as a means for creating regions of unsupported lipid bilayer films. The templates with pores sizes on the order of tens of nanometers were prepared by phase segregation of diblock copolymers on a silicon oxide surface. The polymer templates were either coated with gold or reactively etched to the silicon surface to form hydrophilic (gold or silicon oxide, respectively) surfaces. Finally, we deposited bilayers of dimyrystoyl phophatidylcholine on the templates either by a combination of Langmuir-Blodgett deposition and vesicle fusion or by vesicle fusion alone. We present neutron reflectometry and Atomic Force Microscopy measurements of these various samples and show that we have achieved the desired architecture over large areas of the substrate.

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