Directed self-assembly of lipid bilayer membranes within a microfluidic device

COLL 71

Noah Malmstadt, malmstad@usc.edu, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 216, Los Angeles, CA 90089, Jason L. Poulos, jpoulos@ucla.edu, Department of Bioengineering, University of California, Los Angeles, 420 Westwood Plaza, 5121 Engineering V, Los Angeles, CA 90095, and Jacob Schmidt, schmidt@seas.ucla.edu, Department of Bioengineering, UCLA, 5121G Engineering V, 410 Westwood Plaza, Los Angeles, CA 90095.
Membrane channel proteins are major targets of drug discovery and screening and recent work has also shown their potential as single molecule sensors. Conventional membranes housing these proteins can be problematic to form and are extremely fragile, forming a major roadblock to channel protein-based sensing technology. Furthermore the membrane formation process involves the manipulation of two or three phases, which problematizes its adaptation to a microfluidic format. We have overcome these difficulties and recently created a novel microfluidic device capable of automated microfluidic membrane formation (“Automated Formation of Lipid-Bilayer Membranes in a Microfluidic Device” Noah Malmstadt, Michael A. Nash, Robert F. Purnell, and Jacob J. Schmidt, Nano Lett. 6(9), 1961-1965 (2006)). The automated microfluidic formation device enables the creation and manipulation of lipid membranes through a novel membrane formation process. The microfluidic channels are molded in PDMS, and the solvent absorptive properties of this elastomer are used to mediate solvent extraction from a droplet of lipid-containing organic solvent. The extraction of solvent from the lipid droplet slowly concentrates the lipid, allowing a continuous lipid layer to form at the droplet interface which meets the other side of the droplet to form a bilayer membrane when most of the solvent is extracted. These membranes are high quality, forming greater than gigaohm seals and can support the incorporation and measurement of single channel proteins. This new method of membrane formation lends itself very readily to further miniaturization and in an array format. We show the formation and measurement of these membranes and the proteins contained therein, and the development of an array-based device for automated high-throughput measurements of channel proteins. This technology has potential applications for drug discovery and screening as well as small molecule sensing.
 

Biological Surface Chemistry
8:30 AM-11:50 AM, Monday, March 26, 2007 McCormick Place South -- Room S404A, Level 4, Oral

Division of Colloid & Surface Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007