Effect of extrusion pressure and lipid properties on the size and polydispersity of lipid vesicles.

The production of vesicles, spherical shells formed from lipid bilayers, is an important aspect of their recent application to drug delivery technologies. One popular production method involves pushing a lipid suspension through cylindrical pores in polycarbonate membranes. However, the actual mechanism by which the polydisperse, multilamellar lipid suspension breaks up into a relatively monodisperse population of vesicles is not well understood. To learn about factors influencing this process, we have characterized vesicles produced under different extrusion parameters and from different lipids. We find that extruded vesicles are only produced above a certain threshold extrusion pressure and have sizes that depend on the extrusion pressure. The minimum pressure appears to be associated with the lysis tension of the lipid bilayer rather than any bending modulus of the system. The flow rate of equal concentration lipid solutions through the pores, after being corrected for the viscosity of water, is independent of lipid properties.

[1]  Evans,et al.  Entropy-driven tension and bending elasticity in condensed-fluid membranes. , 1990, Physical review letters.

[2]  R. Macdonald,et al.  Small-volume extrusion apparatus for preparation of large, unilamellar vesicles. , 1991, Biochimica et biophysica acta.

[3]  E. Evans,et al.  Osmotic properties of large unilamellar vesicles prepared by extrusion. , 1993, Biophysical journal.

[4]  S. Fujime,et al.  [Dynamic light-scattering]. , 1985, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme.

[5]  L. Mayer,et al.  Vesicles of variable sizes produced by a rapid extrusion procedure. , 1986, Biochimica et biophysica acta.

[6]  S Kölchens,et al.  Quasi-elastic light scattering determination of the size distribution of extruded vesicles. , 1993, Chemistry and physics of lipids.

[7]  Dennis E. Koppel,et al.  Analysis of Macromolecular Polydispersity in Intensity Correlation Spectroscopy: The Method of Cumulants , 1972 .

[8]  Mason,et al.  Emulsification in Viscoelastic Media. , 1996, Physical review letters.

[9]  Kroll,et al.  Driven transport of fluid vesicles through narrow pores. , 1995, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[10]  R. Bruinsma.  RHEOLOGY AND SHAPE TRANSITIONS OF VESICLES UNDER CAPILLARY FLOW , 1996 .

[11]  T. E. Thompson,et al.  A possible mechanism for vesicle formation by extrusion. , 1994, Biophysical journal.

[12]  Erich Sackmann,et al.  Bending elastic moduli of lipid bilayers : modulation by solutes , 1990 .

[13]  J. Philippot,et al.  Liposomes as Tools in Basic Research and Industry , 1994 .

[14]  D. Roux,et al.  Effect of shear on a lyotropic lamellar phase , 1993 .

[15]  R. Pecora.  Dynamic Light Scattering , 1985 .

[16]  M. Bally,et al.  Production of large unilamellar vesicles by a rapid extrusion procedure: characterization of size distribution, trapped volume and ability to maintain a membrane potential. , 1985, Biochimica et biophysica acta.

[17]  P. Cullis,et al.  Generation of large unilamellar vesicles from long-chain saturated phosphatidylcholines by extrusion technique , 1989 .