A fluctuation wave mechanism of membrane electrofusion

Abstract

Fusion requires close approach and destabilization of the membranes and the intervening liquid layer. Due to thermal motion or other reasons the thickness of the membranes and the distance between them fluctuate. External electric fields can change the amplitude of the fluctuations and induce instability. On oen hand, the field can induce attractive forces between the membranes. On the other hand, it can destabilize and rupture the membranes themselves. The kinetics of the fluctuation wave growth depends on the viscosities of the membranes and the medium between them as well as the other physical parameters and the amplitude of the applied electric field. We suggested a simple model to calculate the characteristic times of unstable fluctuation waves which can lead to fusion. The basic conclusion is that the fluctuation-wave mechanism is kinetically favorable for establishing close local contact between the membranes. It can also be responsible for formation of hydrophilic pores in the membranes which can serve as sites for inducing fusion. This mechanism is operating for the initial stages of electrofusion. These results do not disprove other possible mechanisms.