INTERACTION OF SHORT-CHAIN LECITHIN WITH LONG-CHAIN PHOSPHOLIPIDS - CHARACTERIZATION OF VESICLES THAT FORM SPONTANEOUSLY
INTERACTION OF SHORT-CHAIN LECITHIN WITH LONG-CHAIN PHOSPHOLIPIDS - CHARACTERIZATION OF VESICLES THAT FORM SPONTANEOUSLY
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DOI：
10.1021/bi00358a012
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发表时间：
1986-05-20
期刊：
影响因子：
2.9
通讯作者：
ROBERTS, MF
中科院分区：
文献类型：
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作者：
GABRIEL, NE;ROBERTS, MF
长链磷脂水悬浮液混合后自发形成稳定的单层囊泡（合成、饱和和天然存在的磷脂酰胆碱、磷脂酰乙醇胺和鞘磷脂），含少量短链卵磷脂（6-8个碳的脂肪酸链长）已经通过使用NMR光谱，负染色电子显微镜，差示扫描量热法，和傅里叶变换红外（FTIR）光谱。这种囊泡制备方法可以产生尺寸范围为100至大于1000埃的双层囊泡。短链卵磷脂和长链卵磷脂在室温下以其凝胶状态的组合产生相对小的单层囊泡，而使用长链卵磷脂以其液晶状态产生大的单层囊泡。短链卵磷脂剂量的长度不影响囊泡的大小分布，短链与长链组分的比例影响得一样多。一般来说，额外的短链会降低平均囊泡大小。胆固醇的掺入可以影响囊泡的大小，其中胆固醇在短链卵磷脂胶束中的溶解度极限控制任何大小变化。如果胆固醇的量低于胶束短链卵磷脂的溶解度极限，则向囊泡双层中加入胆固醇对囊泡大小没有影响;如果加入更多的胆固醇，则观察到颗粒生长。囊泡形成的饱和长链卵磷脂和短链物种表现出类似的相变行为和焓值的小单层囊泡的纯长链卵磷脂通过超声处理制备。随着短链/长链囊泡的尺寸减小，相变温度降低至超声处理的单层囊泡所观察到的温度。FTIR光谱证实短链脂质在囊泡双层中的掺入不会显著改变长链脂质的左右键构象（即，它们在凝胶状态下的transness和在液晶状态下多个交错键的存在）。
Stable unilamellar vesicles formed spontaneously upon mixing aqueous suspensions of long-chain phospholipid (synthetic, saturated, and naturally occurring phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin) with small amounts of short-chain lecithin (fatty acid chain lengths of 6-8 carbons) have been characterized by using NMR spectroscopy, negative staining electron microscopy, differential scanning calorimetry, and Fourier transform infrared (FTIR) spectroscopy. This method of vesicle preparation can produce bilayer vesicles spanning the size range 100 to greater than 1000 .ANG.. The combination of short-chain lecithin and long-chain lecithin in its gel state at room temperature produces relatively small unilamellar vesicles, while using long-chain lecithin in its liquid-crystalline state produces large unilamellar vesicles. The length of the short-chain lecithin doses not affect the size distribution of the vesicles as much as the ratio of short-chain to long-chain components. In general, additional short-chain decreases the average vesicle size. Incorporation of cholesterol can affect vesicle size, with the solubility limit of cholesterol in short-chain lecithin micelles governing any size change. If the amount of cholesterol is below the solubility limit of micellar short-chain lecithin, then the addition of cholesterol to the vesicle bilayer has no effect on the vesicle size; if more cholesterol is added, particle growth is observed. Vesicles formed with a saturated long-chain lecithin and short-chain species exhibit similar phase transition behavior and enthalpy values to small unilamellar vesicles of the pure long-chain lecithin prepared by sonication. As the size of the short-chain/long-chain vesicles decreases, the phase transition temperature decreases to temperatures observed for sonicated unilamellar vesicles. FTIR spectroscopy confirms that the incorporation of the short-chain lipid in the vesicle bilayer does not drastically alter the gauche bond conformation of the long-chain lipids (i.e., their transness in the gel state and the presence of multiple gauche bonds in the liquid-crystalline state).