Interactions of DMPC and DMPC/gemini liposomes with the cell membrane investigated by electrorotation

The electrorotation technique was utilized to investigate the interactions between a mouse fibroblast cell line and zwitterionic liposomes formed by a natural phospholipid or cationic liposomes formulated with the same phospholipid and a cationic gemini surfactant. The application of this technique allowed an accurate characterization of the passive dielectric behavior of the plasma membrane by the determination of its specific capacitance and conductance. Changes of these parameters, upon interaction with the liposomes, are related to variations in the structure and or in the transport properties of the membrane. Cells were exposed to both types of liposomes for 1 or 4 h. Electrorotation data show a dramatic reduction of the dielectric parameters of the plasma membrane after one hour treatment. After 4 h of treatment the effects are still observed only in the case of the cationic liposomes. Surprisingly, these same treatments did not cause a relevant biological damage as assessed by standard viability tests. A detailed discussion to rationalize this phenomenon is presented.

R. Cosimati et al. interactions of DMPC and DMPC/gemini liposomes with the cell plasma membrane investigated by electrorotation.Figure optionsDownload high-quality image (200 K)Download as PowerPoint slideHighlights
► Plasma-membrane specific capacitance and conductance evaluated by electrorotation.
► Interaction with liposomes determines structure and/or transport variations.
► The effect is transient or persistent depending on the liposome species.
► Both liposome species do not exert relevant effects on the cell survival.