Shape and Size of a Nonionic Surfactant Micelle. Triton X-100 in Aqueous Solution

H. Hasko Paradies

J. Phys. Chem. 1980, 84, 599-607

Phase Separation of Polymerized Mixed Liposomes: Analysis of Release Behavior of Entrapped Molecules with Skeletonization

Shinji Takeoka, Hiromi Sakai, Hiroyuki Ohno,+ and Eishun Tsuchida'

Macromolecules 1991,24, 1279-1283

The mixed liposomes, composed of a polymerizable lipid, 1,2-bis(2,4-octadecadienoyl)-snglycero-3-phosphorylcholine(D ODPC), and nonpolymerizable membrane constituents, DPPC, cholesterol, and sodium didodecyl phosphate, were prepared by an extrusion method. After polymerization, onpolymerizable constituents were removed to obtain the polymerized framework of the liposome (the skeletonized liposome). The release of small molecules from the skeletonized liposomes through resulting holes was analyzed. A 5(6)-carboxyfluorescein (CF) and saccharides with various molecular weights were applied as release molecules. The molecular weight of dextran, whose retention ratio in the skeletonized liposomes is 5096, relates to the apparent size of the holes, i.e., the apparent domain size of the phase separation of a polymerized mixed liposome. The size of the holes increases with an increase in the mole fraction of nonpolymerizable lipids. This also depends on the polymerization temperature and the structure of nonpolymerizable lipids.

Thermodynamics of micelle formation and surface chemical behavior of p-tert-Octylphenoxyethylene Ether (TritonX-100) in Aqueous Medium

J. Surface Sci. Technol., Vol 17, no.1-2, pp.1-15, 2001

LIPOSOMES OF CONTROLLABLE SIZE IN THE RANGE OF 40 TO 180 nm BY DEFINED DIALYSIS OF LIPID/DETERGENT MIXED MICELLES

OTMAR ZUMBUEHL and HANS GEORG WEDER

Biochimica et Biophysica Acta, 640 (1981) 252-262

Liposomes, in the size range of 40--180 nm, are formed when lipid and additives are solubllized with detergent, yielding defined mixed micelles, and the detergent is subsequently removed by controlled dialysis. Their most important properties are that they are indeed unilamellar with usefully large encapsulated volumes and are homogeneous in size. Liposomes have been formed from both natural and synthetic phospholipids with cholesterol and charged molecules added. This relatively simple technique may be particularly useful for encapsulating drugs, enzymes and other macromolecules and in studies of reconstitution of membrane proteins.

Direct formation of mixed micelles in the solubilization of phospholipid liposomes by Triton X-100

FEBS Letters 426 (1998) 314-318

The vesicle to micelle transition which results in the interaction of the Triton X-100 surfactant with phosphatidylcholine vesicles was studied by means of dynamic light scattering (at different reading angles) and by freeze-fracture electron microscopy techniques. Vesicle solubilization was produced by the direct formation of mixed micelles without the formation of complex intermediate aggregates. Thus, vesicle to micelle transformation was mainly governed by the progressive formation of mixed micelles within the bilayer. A subsequent separation of these micelles from the liposome surface (vesicle perforation by the formation of surfactant-stabilized holes on the vesicle surface) led to a complete solubilization of liposomes.

Temperature Dependence of Triton X-100 Micelle Size and Hydration

Kiril Streletzky and George D. J. Phillies

Langmuir 1996,11, 42-47

Quasi-elastic light scattering spectroscopy was used to measure the mutual diffusion coefficient, D of Triton X-100 micelles in aqueous solution and the translational diffusion coefficient, D, of mesoscopic probes in the same solutions. We apply conventional hydrodynamic treatments of diffision under the assumption that Triton X-100 minimal micelles are adequately represented as hard spheres. Dm and D, measured at a series of surfactant concentrations are used to infer the micelle radius, am, aggregation number, N, and degree of hydration, 6, for temperatures 10 5 T 5 50 "C. As T is increased toward the cloud point, am and N increase, the increase in N being especially dramatic above 40 "C, 6 at first increases but then tends to saturate with increasing T.

The Size, Shape, and Hydration of Nonionic Surfactant Micelles. Triton X-100

Robert J. Robson and Edward A. Dennis
The Journal of Physical Chemistry, Vol. 81, No. 11, 1977

Calculations of the size, shape, and hydration of micelles composed of the nonionic surfactant Triton X-100 were performed based on molecular weight and intrinsic viscosity data. Geometrical considerations show that if the hydrophobic core as well as the whole micelle is spherical, then its structure cannot contain the distinctpolar and apolar regions that are classically assumed for micelles. On the other hand, ellipsoids of revolution would be consistent with a classical micellar structure and an oblate rather than a prolate ellipsoid would be most consistent with intrinsic viscosity measurements and volume calculations.