Presenter Information

Petia Vlahovska, Brown University

Location

Cherry Auditorium, Kirk Hall

Start Date

9-25-2014 1:00 PM

Description

Living cells maintain electric potential difference across their plasma membrane. Changes in the transmembrane electric field are biologically important signals in physiological processes such as electric-field-directed cell migration in development and regeneration. Pulsed electric fields are used to open pores in the membrane, which enable the delivery of material inside the cell, e.g. for gene transfection.

I will present our theoretical and experimental work on the deformation and stability of biomimetic membranes (bilayers assembled from lipids or polymers) in electric fields. Gant vesicles exposed to DC pulses adopt peculiar drum-like shapes and may collapse. Our experiments suggest that the edge separates porated (conducting) and intact (insulating) regions of the membrane. The time dependence of the edge location can serve as a quick method to estimate the critical voltage for membrane poration. Electrohydrodynamic analysis of the collapse dynamics shows that membrane conductance and asymmetry in the embedding electrolyte solutions destabilize the interface; membrane viscosity slows down the growth of the instability. In the case of multicomponent membranes, electric fields induce reversible phase separation.

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Sep 25th, 1:00 PM

Living on the edge: voltage-driven extreme deformation of bilayer membranes

Cherry Auditorium, Kirk Hall

Living cells maintain electric potential difference across their plasma membrane. Changes in the transmembrane electric field are biologically important signals in physiological processes such as electric-field-directed cell migration in development and regeneration. Pulsed electric fields are used to open pores in the membrane, which enable the delivery of material inside the cell, e.g. for gene transfection.

I will present our theoretical and experimental work on the deformation and stability of biomimetic membranes (bilayers assembled from lipids or polymers) in electric fields. Gant vesicles exposed to DC pulses adopt peculiar drum-like shapes and may collapse. Our experiments suggest that the edge separates porated (conducting) and intact (insulating) regions of the membrane. The time dependence of the edge location can serve as a quick method to estimate the critical voltage for membrane poration. Electrohydrodynamic analysis of the collapse dynamics shows that membrane conductance and asymmetry in the embedding electrolyte solutions destabilize the interface; membrane viscosity slows down the growth of the instability. In the case of multicomponent membranes, electric fields induce reversible phase separation.