Fusion of model lipid membranes: timescales and some applications – Niels Bohr Institute - University of Copenhagen

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Fusion of model lipid membranes: timescales and some applications

Dr. Rumiana DIMOVA
Max Planck Institute of Colloids and Interfaces
Golm, 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, signalling 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
recently.  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
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.