Diffusion behavior of lipid vesicles in entangled polymer solutions.
AUTOR(ES)
Cao, X
RESUMO
Dynamic light scattering was used to follow the tracer diffusion of phospholipid/cholesterol vesicles in aqueous polyacrylamide solutions and compared with the diffusive behavior of polystyrene (PS) latex spheres of comparable diameters. Over the range of the matrix concentration examined (Cp = 0.1-10 mg/ml), the diffusivities of the PS spheres and the large multilamellar vesicles exhibited the Stokes-Einstein (SE) relation, while the diffusivity of the unilamellar vesicles did not follow the increase of the solution's viscosity caused by the presence of the matrix molecules. The difference between the diffusion behaviors of unilamellar vesicles and hard PS spheres of similar size is possibly due to the flexibility of the lipid bilayer of the vesicles. The unilamellar vesicles are capable of changing their shape to move through the entangled polymer solution so that the hindrance to their diffusion due to the presence of the polymer chains is reduced, while the rigid PS spheres have little flexibility and they encounter greater resistance. The multilamellar vesicles are less flexible, thus their diffusion is similar to the hard PS spheres of similar diameter.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1181094Documentos Relacionados
- Macromolecular diffusion in crowded solutions.
- Instability of coated vesicles in concentrated sucrose solutions.
- Tracer diffusion of globular proteins in concentrated protein solutions.
- beta-Endorphin: formation of alpha-helix in lipid solutions.
- DIFFUSION COEFFICIENTS IN POLYMER-SOLVENT SYSTEMS FOR HIGHLY CONCENTRATED POLYMER SOLUTIONS