Scanning Calorimetry Studies of the Micelle-Vesicle Transition In Phospholipids

已知磷脂和洗涤剂的混合物在适当条件下会发生胶束和囊泡形式之间的转化。转化过程发生在洗涤剂和磷脂组成的一个狭窄范围内，似乎涉及到与存在于过渡区两个极端边界的囊泡或胶束完全不同的中间结构。对过渡区内的过渡特征和过渡形式的性质了解甚少。本项目涉及用差示扫描量热法研究几种洗涤剂-磷脂体系的组成，特别是靠近胶束和囊泡之间的过渡区域。磷脂和洗涤剂的水相混合物中的脂质被认为以几种不同的结构形式存在，这取决于溶液的组成和条件。在低摩尔比的洗涤剂与脂质形成单层囊泡，而在高摩尔比胶束结构占上风。这些限制结构之间的转换是一个基本问题，它对磷脂的物理和化学行为的几个重要领域具有影响。本项目的研究结果对进一步了解胆盐和磷脂混合物的膜重构方法、囊泡给药方法和脂质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.