Fusion of liposome membranes by the n-alkyl bromides.

It has been found that the n-alkyl bromides are capable of inducing the fusion of unilamellar liposomes. These compounds can bring about fusion of liposomes composed of either pure phosphatidylcholine or phosphatidycholine+phosphatidic acid. Fusion of unilamellar liposomes gives rise to multilamellar structures, the morphology of which has been examined by negative staining and freeze-fracture techniques. It has been shown by microelectrophoresis that the n-alkyl bromides have no effect on the surface charge of liposomes, and fusion has been further characterized by use of light scattering and differential scanning calorimetry, the latter indicating that true mixing of the fatty acyl chains occurs upon fusion. Finally, fusion occurs at n-alkyl bromide levels below that required to saturate the aqueous phase of the system.