title: Block liposomes vesicles of charged lipids with distinctly shaped nanoscale sphere-, pear-, tube-, or rod-segments.
abstract: We describe the preparation and characterization of block liposomes, a new class of liquid (chain-melted) vesicles, from mixtures of the highly charged (+16 e) multivalent cationic lipid MVLBG2 and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC). Block liposomes (BLs) consist of distinct spherical, tubular vesicles, and cylindrical micelles that remain connected, forming a single liposome. This is in contrast to typical liposome systems, where distinctly shaped liposomes are macroscopically separated. In a narrow composition range (8-10 mol% MVLBG2), an abundance of micrometer-scale BLs (typically sphere-tube-sphere triblocks) is observed. Cryo-TEM reveals that BLs are also present at the nanometer scale, where the blocks consist of distinctly shaped nanoscale spheres, pears, tubes, or rods. Pear-tube diblock and pear-tube-pear triblock liposomes contain nanotubes with inner lumen diameter 10-50 nm. In addition, sphere-rod diblock liposomes are present, containing rigid micellar nanorods approximately 4 nm in diameter and several microm in length. Block liposomes may find a range of applications in chemical and nucleic acid delivery and as building blocks in the design of templates for hierarchical structures.
authors.affiliation: Materials Department, University of California at Santa Barbara, Santa Barbara, California, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Zidovska
authors.forename: Kai K
authors.initials: KK
authors.lastname: Ewert
authors.forename: Joel
authors.initials: J
authors.lastname: Quispe
authors.forename: Bridget
authors.initials: B
authors.lastname: Carragher
authors.forename: Clinton S
authors.initials: CS
authors.lastname: Potter
authors.forename: Cyrus R
authors.initials: CR
authors.lastname: Safinya
mesh_terms: D020285:Cryoelectron Microscopy; D008081:Liposomes; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D036103:Nanotechnology; D010713:Phosphatidylcholines / Q000737:chemistry*
chemical_list: D008081:Liposomes; D008823:Micelles; D010713:Phosphatidylcholines; C017251:1,2-oleoylphosphatidylcholine