DENSITY-BASED SEPARATION OF LIPOSOMES BY GLYCEROL GRADIENT CENTRIFUGATION
DENSITY-BASED SEPARATION OF LIPOSOMES BY GLYCEROL GRADIENT CENTRIFUGATION
复制标题
DOI：
10.1016/0003-2697(86)90316-7
复制
发表时间：
1986-11-15
影响因子：
2.9
通讯作者：
SCARBOROUGH, GA
中科院分区：
文献类型：
--
作者：
GOORMAGHTIGH, E;SCARBOROUGH, GA
当离心至接近平衡时，超声处理的大豆磷脂脂质体（asolectin）几乎分布在19-22%（v/v）甘油梯度中。在相同梯度上再离心时，从这种梯度中的几个位置选择的脂质体作为窄带迁移到接近其原始位置的位置，表明第一梯度中的脂质体分布是基于密度的分级的结果。分子筛色谱、浊度和截留体积测量表明脂质体密度与其大小定性相关，较大的脂质体比较小的脂质体更致密。通过负染色制备物的电子显微镜获得的尺寸估计表明分级分离对于直径范围为200至600埃的脂质体是有效的，最大效率在200-300埃的范围内。有趣的是，高浓度的脂质体提高了分级过程的效率。脂质体密度的大小依赖性被证明不是由于不同的甘油渗透性或脂质组成，因此最有可能是由于个别磷脂分子的特定体积的变化，由于脂质体的曲率。最后，在液氮中冷冻甘油梯度级分并在-70 ℃下储存不会改变分离的脂质体的大小。建议脂质体的甘油密度梯度分级可以是用于获得大量和高浓度的合理均匀尺寸的脂质体的有用的通用方法。
Sonicated liposomes of soybean phospholipids (asolectin) distribute nearly throughout a 19-22% (v/v) glycerol gradient when centrifuged to near equilibrium. Upon recentrifugation on an identical gradient, liposomes selected from several positions in such a gradient migrate as narrow bands to positions close to their original positions, indicating that the liposome distribution in the first gradient is the result of a density-based fractionation. Molecular sieve chromatography, turbidity, and trapped volume measurements indicate that the liposome densities are qualitatively related to their size, with the larger liposomes more dense than the smaller ones. Size estimates obtained by electron microscopy of negatively stained preparations indicate that the fractionation is effective for liposomes with diameters ranging from 200 to 600 .ANG., with maximum efficiency in the range 200-300 .ANG. where the majority of the liposomes is found. Interestingly, high concentrations of liposomes improve the efficiency of the fractionation procedure. The size dependence of liposome density is shown not to be due to differential glycerol permeability or lipid composition, and is therefore most likely due to variations in the specific volumes of the individual phospholipid molecules owing to the curvature of the liposomes. Finally, freezing of the glycerol gradient fractions in liquid N2 and storage at -70.degree.C does not modify the size of the isolated liposomes. It is suggested that glycerol density gradient fractionation of liposomes could be a useful general method for obtaining liposomes of reasonably uniform size in large quantities and high concentrations.