Cationic Liposome-Microtubule Complexes: Pathways to the Formation of Two-State Lipid-Protein Nanotubes with Open or Closed Ends

Intermolecular interactions between charged membranes and biological polyelectrolytes, tuned by physical parameters, which include the membrane charge density and bending rigidity, the membrane spontaneous curvature, the biopolymer curvature, and the overall charge of the complex, lead to distinct s...

Full description

Saved in:
Bibliographic Details
Published inProceedings of the National Academy of Sciences - PNAS Vol. 102; no. 32; pp. 11167 - 11172
Main Authors Raviv, Uri, Needleman, Daniel J., Li, Youli, Miller, Herbert P., Wilson, Leslie, Safinya, Cyrus R., Fisher, Michael E.
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 09.08.2005
National Acad Sciences
Subjects
Bending
Charge density
Curvature
Cytoplasmic Vesicles - chemistry
Drug Delivery Systems - methods
Electrolytes - chemistry
Electron density
Electrostatics
Lipids
Liposomes - chemistry
Microscopy, Electron
Microtubules - chemistry
Models, Molecular
Nanotubes
Nanotubes - chemistry
Oligomers
Physical Sciences
Polymers - chemistry
Propane
Quaternary ammonium compounds
Synchrotrons
Tubulin - chemistry
Online AccessGet full text

Cover

More Information
Summary:Intermolecular interactions between charged membranes and biological polyelectrolytes, tuned by physical parameters, which include the membrane charge density and bending rigidity, the membrane spontaneous curvature, the biopolymer curvature, and the overall charge of the complex, lead to distinct structures and morphologies. The self-assembly of cationic liposome-microtubule (MT) complexes was studied, using synchrotron x-ray scattering and electron microscopy. Vesicles were found to either adsorb onto MTs, forming a "beads on a rod" structure, or undergo a wetting transition and coating the MT. Tubulin oligomers then coat the external lipid layer, forming a tunable lipid-protein nanotube. The beads on a rod structure is a kinetically trapped state. The energy barrier between the states depends on the membrane bending rigidity and charge density. By controlling the cationic lipid/tubulin stoichiometry it is possible to switch between two states of nanotubes with either open ends or closed ends with lipid caps, a process that forms the basis for controlled chemical and drug encapsulation and release.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
Edited by Michael E. Fisher, University of Maryland, College Park, MD, and approved June 14, 2005
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: PLC, polyelectrolyte–lipid complex; MT, microtubule; SAXRD, small angle x-ray diffraction; TEM, transmission electron microscopy; LPN, lipid–protein nanotube; BOR, beads on a rod; DLTAP, dilauryl(C12:0)-trimethyl ammonium propane; DOTAP, dioleoyl(C18:1)-trimethyl ammonium propane; DPTAP, dipalmitoyl(C16:0)-trimethyl ammonium propane; PC, phosphatidylcholine; DLPC, dilauryl(C12:0)-PC; DOPC, dioleoyl(C18:1)-PC; DPPC, dipalmitoyl(C16:0)-PC.
To whom correspondence may be addressed. E-mail: raviv@mrl.ucsb.edu or safinya@mrl.ucsb.edu.
Author contributions: U.R. and C.R.S. designed research; U.R. and D.J.N. performed research; U.R., Y.L., H.P.M., and L.W. contributed new reagents/analytic tools; U.R. and C.R.S. analyzed data; and U.R. and C.R.S. wrote the paper.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0502183102