Abstract
Hydration of single or mixed phospholipids or lipid protein mixtures at low ionic strength results in the formation of a population of large, solvent free, single bilayer vesicles with included volumes of up to 300 microliters/mumol lipid. Their size ranges from 0.1 to 300 microns and they can be sorted out according to size by centrifugation. When formed in distilled water their internal solution has a conductivity of 20-50 microseconds/cm-1, an osmolarity of 0.5-5 mOsM, and a density of 1.0005-1.001. The osmotic pressure produced by the internal solutes cause a surface stress of 25 dyn/cm for a 20-microns vesicle. Their elastic constant ranges from 75-150 dyn/cm. During formation they can internalize particles such as latex beads or cell nuclei. They can be impaled with microelectrodes, or patch clamped. They can also be sealed to a small Vaseline-treated hole in a thin partition between two aqueous compartments. Sealing occurs in two stages. In the first stage sealing resistance is similar to that seen with patch-clamp pipettes. In the second stage, a much tighter seal is obtained. After sealing, the smaller portion of the sealed vesicle can be selectively broken by an electric shock leaving a single membrane across the hole. The capacitance and resistance of such membranes, in the presence of 10 mM NaCl, are approximately 0.7 microF/cm2 and 10(8) omega cm2 for pure lipid vesicles. Gramicidin increases the membrane conductance and monazomycin induces voltage-dependent gating thus providing further evidence that the vesicles are bounded by a single bilayer.
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- Darszon A., Vandenberg C. A., Schönfeld M., Ellisman M. H., Spitzer N. C., Montal M. Reassembly of protein-lipid complexes into large bilayer vesicles: perspectives for membrane reconstitution. Proc Natl Acad Sci U S A. 1980 Jan;77(1):239–243. doi: 10.1073/pnas.77.1.239. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gasko O. D., Knowles A. F., Shertzer H. G., Suolinna E. M., Racker E. The use of ion-exchange resins for studying ion transport in biological systems. Anal Biochem. 1976 May 7;72:57–65. doi: 10.1016/0003-2697(76)90506-6. [DOI] [PubMed] [Google Scholar]
- Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
- Kwok R., Evans E. Thermoelasticity of large lecithin bilayer vesicles. Biophys J. 1981 Sep;35(3):637–652. doi: 10.1016/S0006-3495(81)84817-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MUELLER P., RUDIN D. O., TIEN H. T., WESCOTT W. C. Reconstitution of cell membrane structure in vitro and its transformation into an excitable system. Nature. 1962 Jun 9;194:979–980. doi: 10.1038/194979a0. [DOI] [PubMed] [Google Scholar]
- Montal M., Mueller P. Formation of bimolecular membranes from lipid monolayers and a study of their electrical properties. Proc Natl Acad Sci U S A. 1972 Dec;69(12):3561–3566. doi: 10.1073/pnas.69.12.3561. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mueller P., Rudin D. O. Resting and action potentials in experimental bimolecular lipid membranes. J Theor Biol. 1968 Feb;18(2):222–258. doi: 10.1016/0022-5193(68)90163-x. [DOI] [PubMed] [Google Scholar]
- Reeves J. P., Dowben R. M. Formation and properties of thin-walled phospholipid vesicles. J Cell Physiol. 1969 Feb;73(1):49–60. doi: 10.1002/jcp.1040730108. [DOI] [PubMed] [Google Scholar]
- Wolf D. E., Henkart P., Webb W. W. Diffusion, patching, and capping of stearoylated dextrans on 3T3 cell plasma membranes. Biochemistry. 1980 Aug 19;19(17):3893–3904. doi: 10.1021/bi00558a002. [DOI] [PubMed] [Google Scholar]