Biophysical studies on polymer-sandwiched lipid bilayers

PHYS 481

Sumit Garg, sgarg@iupui.edu1, Jay X. Tang, jay_tang@brown.edu2, Christoph A Naumann, naumann@chem.iupui.edu1, and Juergen Ruehe, ruehe@imtek.de3. (1) Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, 402 N. Blackford St., LD 326, Indianapolis, IN 46202, (2) Department of Physics, Brown University, 184 Hope Street, Box 1843, Brown University, Providence, RI 02912, (3) Department of Chemistry and Physics of Interfaces, Institute for Microsystem Technology, University of Freiburg, Georges-Koehler-Allee 103, Freiburg, 79110, Germany
We report on epifluorescence and single molecule fluorescence microscopy studies on planar lipid bilayers containing raft-mimicking lipid mixtures, where the bilayer is sandwiched between two polymeric environments of different persistence length, the flexible poly(methyloxazoline) (PMOx) and the semiflexible F-actin. Several types of polymer-bilayer linkages are compared. Interestingly, our studies show that the domain size in the presence of F-actin is affected significantly if the bilayer contains some negatively charged lipids, but does not show measurable changes in the absence of such lipids. Domain sizes are also altered if PMOx is tethered to the bilayer using high tethering densities. Bilayer diffusion properties are only moderately influenced due to F-actin coupling, whereas a significant drop in lateral mobility is observed at elevated PMOx-tethering densities. The experiments presented provide new insight of how electrostatic and mechanical membrane properties in complex membrane architectures may affect domain size and membrane fluidity.

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006