Scanning Calorimetry Studies of the Micelle-Vesicle Transition In Phospholipids

众所周知，磷脂和洗涤剂的混合物在适当的条件下会在胶束和囊泡之间发生转化。转变过程发生在洗涤剂和磷脂组成的很小范围内，并且似乎涉及到中间结构，这些结构与存在于过渡区两个极端边界的囊泡或胶束有很大不同。关于过渡区中跃迁的特征和跃迁形式的性质，人们知之甚少。这个项目涉及用差示扫描量热法研究几种洗涤剂-磷脂体系，特别是在靠近胶束和小泡之间的过渡区的成分。磷脂和洗涤剂的水混合物中的脂类被认为以几种不同的结构形式存在，这取决于溶液中的组成和条件。当洗涤剂与脂类的摩尔比较低时，会形成单层小泡，而在较高的摩尔比时，会形成胶束结构。这些限制结构之间的转变是一个基本问题，它涉及到与磷脂的物理和化学行为有关的几个重要领域。本项目的研究结果对于更好地理解胆盐和磷脂胆汁混合物中的膜重建方法、囊泡给药方法和脂类转运机制具有重要意义。

Mixtures of phospholipid and detergents are known to undergo transformation between micelle and vesicle forms under proper conditions. The transformation process occurs within a narrow range of compositions of detergent and phospholipid and seems to involve intermediate structures which are quite different from either the vesicles or micelles which exist at the two extreme boundaries of the transition region. Little is known about the characteristics of the transitions in the transition region and the properties of the transitions forms. This project involves the study of several detergent- phospholipid systems by differential scanning calorimetry at compositions particularly close to the transition region between micelles and vesicles. Lipids in aqueous mixtures of phospholipids and detergent are thought to exist in several different structural forms dependent upon the composition and conditions in solution. At low mole ratios of detergent to lipid unilamellar vesicles form, while at high ratios micellar structures prevail. The transition between these limiting structures is a fundamental problem that has implications for several important areas relating to the physical and chemical behavior of phospholipids. The results of this project could be significant for a better understanding of membrane reconstitution methods, vesicular drug delivery methods and the mechanisms of lipid transport in biliary mixtures of bile salts and phospholipids.