Cao X, Bansil R, Gantz D, Moore E W, Niu N, Afdhal N H
Department of Chemistry, Boston University, Massachusetts 02215, USA.
Biophys J. 1997 Oct;73(4):1932-9. doi: 10.1016/S0006-3495(97)78224-9.
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.
动态光散射用于跟踪磷脂/胆固醇囊泡在聚丙烯酰胺水溶液中的示踪扩散，并与直径相当的聚苯乙烯（PS）乳胶球的扩散行为进行比较。在所研究的基质浓度范围内（Cp = 0.1 - 10 mg/ml），PS球和大多层囊泡的扩散系数呈现斯托克斯 - 爱因斯坦（SE）关系，而单层囊泡的扩散系数并不随基质分子存在导致的溶液粘度增加而变化。单层囊泡与类似大小的硬PS球扩散行为的差异可能归因于囊泡脂质双层的柔韧性。单层囊泡能够改变其形状以穿过缠结的聚合物溶液，从而降低聚合物链的存在对其扩散的阻碍，而刚性的PS球柔韧性很小，它们遇到的阻力更大。多层囊泡的柔韧性较差，因此它们的扩散类似于类似直径的硬PS球。
