COLL 155 |
| This project examines the effect of mechanical membrane properties on the adhesion dynamics between, poly (butadiene)-poly (ethylene oxide) [PBD-PEO] copolymer vesicles. The PBD-PEO vesicles were compared to a less stiff model membrane system comprised of poly(dimethylsiloxane)-poly(ethylene oxide)[PDMS-PEO] or phospholipid vesicles which showed 3 distinctive adhesion stages (pre, fast, and final spreading) for spreading The fully biotinylated PEO-PBD vesicles, when held at moderate tensions in micropipettes, did not show significant spreading or vesicle deformation despite irreversible binding between avidin and biotin ligands and receptors, in contrast to the behavior of the more bendable system. Strong cohesive interactions between entangled diblock copolymers might hinder the translational diffusion of ligand-receptors towards the contacting interface resulting in less deformation of membrane at the advancing contact interface; however, when the membrane stress was reduced or when one of the two vesicles was ruptured, the remaining vesicle membrane quickly adhered over substrate vesicle. Similar behavior was observed with PBD-PEO vesicles in depletion force measurements. These results demonstrate that even for thin vesicles, the near surface mechanical properties are important in the ultimate adhesion behavior of vesicles. |
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Fundamental Research in Colloid and Surface Chemistry
6:00 PM-8:00 PM, Monday, August 20, 2007 BCEC -- East Registration, Poster
Division of Colloid & Surface Chemistry |