Regensburg 2004 – scientific programme
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AKB: Biologische Physik
AKB 50: Poster Session "Biological Physics"
AKB 50.54: Poster
Friday, March 12, 2004, 10:30–13:00, B
Fusion of giant vesicles observed with time resolution below a millisecond — •Rumiana Dimova1, Christopher Haluska1, Karin A. Riske1, Valerie Marchi-Arztner1, and Reinhard Lipowsky2 — 1Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Golm, Germany — 2Universite de Rennes, Rennes France
Using optical microscopy and a high speed camera, we are able to record the fusion process with a high temporal resolution of 100us. We consider two model membrane systems: functionalized giant unilamellar vesicles (GUVs) in the presence of multivalent ions, and lipid or polymer GUVs subjected to electrical pulses.
In the first case, we functionalize lecithin membranes with synthetic molecules bearing a ligand, which form complexes with Eu3+ (2:1). Micropipettes are used to manipulate GUV’s and inject Eu3+ solution in the contact zone between two vesicles. The injections induce adhesion and formation of intermembrane complexes, followed by fusion. This system has the potential to mimic the action of fusogenic SNARE proteins and give us a better understanding about fusion in biological membranes.
In the second case, we study the fusion of GUVs made of neutral lipid or diblock copolymer when subjected to electric pulses. We estimate the characteristic times related to the evolution of the fusion neck. In comparison to lipid GUVs, polymer vesicles show much slower relaxation due to the high surface viscosity of their membrane.
In both cases, we detect that the fusion process takes place on the time scale less than half a millisecond.