Liposomes

Liposomes are spherical vesicles with a membrane composed of a lipid bilayer. The lipid bilayer can fuse with other bilayers (e.g., the cell membrane), and so deliver the contents of the liposome to the cell. Whatever media in which liposomes are created is internalized. By making liposomes in a solution of DNA or drugs, which would normally be unable to diffuse through the membrane, these can be (indiscriminately) delivered past the lipid bilayer.