EFFECT OF CHAIN-LENGTH AND LIPID PHASE-TRANSITIONS ON SELECTIVE PERMEABILITY PROPERTIES OF LIPOSOMES
EFFECT OF CHAIN-LENGTH AND LIPID PHASE-TRANSITIONS ON SELECTIVE PERMEABILITY PROPERTIES OF LIPOSOMES
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DOI：
10.1016/0005-2736(75)90003-6
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发表时间：
1975-01-01
期刊：
影响因子：
--
通讯作者：
DEGIER, J
中科院分区：
文献类型：
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作者：
BLOK, MC;VANDERNEUTKOK, ECM;DEGIER, J
本文描述了在横向相分离条件下，脂肪酸链长度对饱和卵磷脂制备的脂质体双分子层的屏障性能的重要性。1. 1.在凝胶到液晶的相变温度以上，饱和卵磷脂（每个酰基链有14个或更多的碳原子）制备的脂质体以稳定的双分子层形式存在，几乎不被离子渗透。2. 2.在远高于过渡温度的温度下，二脲酰磷脂酰胆碱脂质体表现出渗透收缩，这取决于用于产生渗透梯度的溶质的离子大小，表明通过这些不太稳定的双分子层的渗透主要是通过渗透离子的单个扩散进行的。3. 3.在过渡温度附近，脂质体中被困钾的释放增强。然而，增加的程度强烈地依赖于石蜡链的长度。4. 4.从脂质体在转变温度附近的收缩行为的测量可以得出结论，随着渗透离子直径的增加，增加的渗透性降低。这一发现表明，在转变温度下通透性的增加不能归因于脂质体膜的“宏观”破裂。根据液体和固体边界上统计孔隙形成的概率和大小分布，讨论了温度附近的最大渗透率。
This paper describes experiments showing the importance of the fatty acid chain length on the barrier properties of liposomal bilayers, prepared from saturated lecithins, under conditions of lateral phase separation. 1. 1.| Above the gel to liquid crystalline phase transition temperature, liposomes prepared from saturated lecithins with 14 or more carbon atoms per acyl chain exist as stable bilayers, which are practically impermeable to ions. 2. 2.| At temperatures well above the transition temperature dilauroyl phosphatidylcholine liposomes exhibited osmotic shrinkage, which was dependent on the ionic size of the solute used to bring about the osmotic gradient, indicating that the permeation through these less stable bilayers takes place mainly via individual diffusion of the permeating ions. 3. 3.| An enhanced release of trapped potassium from liposomes was demonstrated in the vicinity of the transition temperature. The extent of the increase, however, depended strongly on the length of the paraffin chain. 4. 4.| From measurements of the shrinkage behaviour of liposomes in the vicinity of the transition temperature it is concluded that the increased permeability decreases with increasing diameter of the permeating ion. This finding implies that the increased permeability at the transition temperature cannot be ascribed to “macroscopic” rupture of the liposomal membrane. The maximum permeability in the vicinity of the T c is discussed in terms of probability and size distribution of statistical pore formation at the boundaries of liquid and solid domains.