Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 3: Membranes and Interfaces

BP 3.1: Invited Talk

Monday, March 26, 2007, 14:00–14:30, H43

On the Timescales of Membrane Fusion — •Rumiana Dimova — Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany

Membrane fusion is a vital process as it is involved in many cellular functions and stages of cell life like import of foodstuffs and export of waste, signaling between nerve cells, fertilization, and virus infection. In both the life sciences and bioengineering, controlled membrane fusion has many possible applications, such as drug delivery, gene transfer, chemical microreactors, or synthesis of nanomaterials.

Fusion dynamics is intriguing but microscopy observations with time resolution higher than several milliseconds have not been achieved until now. Using micromanipulation of giant unilamellar vesicles as model membranes one can directly observe membrane fusion. We induce the fusion of giant lipid vesicles in a controlled manner and monitor the fusion dynamics with a temporal resolution of 50 microseconds; see Haluska et al. Proc. Natl. Acad. Sci. USA. 103, 15841-15846 (2006). Two different approaches of inducing directed fusion are used: i) employing synthetic fusogenic molecules incorporated in the membranes, and ii) electrofusion. For both protocols, the opening of the fusion necks is very fast, with an average expansion velocity of centimeters per second. This velocity indicates that the initial formation of a single fusion neck can be completed in a few hundred nanoseconds.