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July 3, 2015


Optical tweezers as a tool for investigating physical properties of phospholipid nanotubes and membrane-binding proteins

Younes Farhangi
NBI, University of Copenhagen, Denmark

Date: July 3, 2015 (Friday)
Time: 10:40 (Mind the unusual time-slot!)
Place: Physics Seminar Room SA 240

HOST: Giovanni Volpe


Phospholipid nanotubes (typically with a radius between 10 and 100 nm) are excellent models for studying the biophysics properties of nanotubes in living cells. In our work, first kink of phospholipid nanotubes were produced by spontaneous swelling method and their stiffness, which is called the persistence length, was measured from their fluctuation.

Second kind of Phospholipid nanotubes (tether) extracted by applying a point force on vesicle’s membrane by optical tweezers. Tethers with different diameter were pulled out of vesicle’s membrane and the optical tweezers force during this process
was measured. The radius of tether calculated from the amount of optical tweezers force and membrane tension. This experiment was conducted in the presence of BAR (Bin-Amphiphysin-Rvs) domain proteins. BAR domain proteins which are called membrane-binding proteins play an important role in membrane-remodeling.

The results revealed that the binding of proteins to phospholipid nanotube causes more curvature on it and makes it thinner in comparison to pure phospholipid nanotube.