Evidence of surfactant-induced formation of transient pores in lipid bilayers by using magnetic-fluid-loaded liposomes

It is often assumed that surfactant-induced permeability of lipid membranes obeys a pore-formation mechanism, but, to date, this has not been totally proven. A novel approach is developed using a magnetic fluid composed of calibrated nanocrystals of maghemite (gamma-Fe2O3) as a permeability marker. It is shown that low amounts of surfactant molecules catalyze the transient opening of unilamellar phospholipid vesicles which permit the passage of 8 nm maghemite nanospheres before closing up.