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Proceedings Paper

Manipulation of lipid bilayer membranes in solution using laser tweezers and microsphere handles
Author(s): Christine D. Keating; Terrence G. D'Onofrio; Anat Hatzor; Amy S. Whelpley; Michael J. Natan; Paul S. Weiss
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Paper Abstract

The local structure of biological membranes is critically important to membrane function. Regions of very high positive and negative curvature are found in the membranes of many cells, and rapid changes in membrane curvature are integral parts of many cell activities (e.g. endo/exocytosis, cell crawling, cell division). Our goal is to understand the effects of changes in local membrane structure on membrane properties. Optical tweezers are used to control the local structure of the lipid bilayer by controlling the curvature of the membrane. We use giant (`cell-sized'), thin-walled vesicles as our membrane models. Optically trapped latex microspheres are used to deform the liposome bilayer, forming large areas of altered membrane curvature. In contrast to literature reports in which 514.5 nm light was used in optical trapping, we have not observed adhesion of uncoated latex microspheres to liposome vesicles, nor have we observed signs of rapidly increased osmotic pressure within irradiated vesicles. This indicates that the longer wavelength used in our studies (647.1 nm) is less damaging to biological membranes. Furthermore, optical trapping of vesicles with coexisting gel and fluid phase lipids did not lead to gross changes in domain structure, which would be expected upon laser-induced heating of the membrane.

Paper Details

Date Published: 26 April 2000
PDF: 9 pages
Proc. SPIE 3924, Molecular Imaging: Reporters, Dyes, Markers, and Instrumentation, (26 April 2000); doi: 10.1117/12.384249
Show Author Affiliations
Christine D. Keating, The Pennsylvania State Univ. (United States)
Terrence G. D'Onofrio, The Pennsylvania State Univ. (United States)
Anat Hatzor, The Pennsylvania State Univ. (United States)
Amy S. Whelpley, The Pennsylvania State Univ. (United States)
Michael J. Natan, The Pennsylvania State Univ. (United States)
Paul S. Weiss, The Pennsylvania State Univ. (United States)

Published in SPIE Proceedings Vol. 3924:
Molecular Imaging: Reporters, Dyes, Markers, and Instrumentation
Darryl J. Bornhop; Kai Licha, Editor(s)

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