Development of robust hydrogel encapsulated membranes for channel protein science and sensing


Tae-Joon Jeon,, Department of Bioengineering, University of California, Los Angeles, 420 Westwood Plaza, Room 5121 Engineering V, Los Angeles, CA 90095, Noah Malmstadt,, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, HED 216, Los Angeles, CA 90089, and Jacob Schmidt,, 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 are extremely fragile and short-lived, limiting channel protein-based sensing technology. We have recently developed a new technique in which lipid bilayer membranes are encapsulated in situ within a hydrogel matrix. (Hydrogel-Encapsulated Lipid Membranes, Tae-Joon Jeon, Noah Malmstadt, and Jacob J. Schmidt, Journal of the American Chemical Society 128, 42-43 (2006)) The hydrogel encapsulated membranes are created by forming a freestanding lipid bilayer membrane in the presence of a hydrogel precursor solution. This solution is then polymerized by UV exposure. We show that these encapsulated membranes are more robust and long-lived than their unencapsulated counterparts as a result of the intimate hydrogel/membrane contact. We have also synthesized a lipid which is able to participate in the polymerization reaction. Membranes created from these cross-linkable lipids can bond directly to the hydrogel matrix, further strengthening the membrane and resulting in further extended lifetimes. We show that these membranes retain the ability to support the incorporation and measurement of single channels. We also show the enhanced membrane stability when the gel is covalently attached to the solid support substrate surrounding the membrane. With supporting evidence supplied by optical microscopy, we will discuss the cause of this enhanced stability and show preliminary studies aimed at cryopreservation of the membranes. Our efforts are aimed at creating a long-lived, stable measurement platform for scientific or technological studies using ion channel proteins. We will also present our latest efforts at incorporating the hydrogel encapsulated membranes into a device format.

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