Liposomes composed of a double-chain cationic amphiphile (Vectamidine) induce their own encapsulation into human erythrocytes

Vectamidine is a liposome-forming double-chain cationic amphiphile. The pre sent work was aimed to microscopically study the interactions of Vectamidin e liposomes with the human erythrocyte plasma membrane. Vectamidine rapidly induced stomatocytic shapes. Attachment of Vectamidine liposomes to the er ythrocyte induced a strong local invagination of the membrane. This frequen tly resulted in a complete encapsulation of the liposome. Liposomes compose d of phosphatidylcholine (neutral) or phosphatidylserine/phosphatidylcholin e (anionic) did not perturb the erythrocyte shape. Our results indicate tha t besides an attraction of Vectamidine liposomes to the plasma membrane, th ere is a preference of Vectamidine for the inner bilayer leaflet. We sugges t that cationic amphiphiles may transfer from membrane-attached liposomes t o the plasma membrane and then translocate to the inner bilayer leaflet whe re they induce a strong local inward bending of the plasma membrane resulti ng in an encapsulation of the liposome. (C) 1999 Elsevier Science B.V. All rights reserved.