Construction of Monomolecular Membrane with Different Surface Properties and Electron Transfer

以囊泡的形式制备了内外表面性质不同的单分子膜。本研究的目的是研究这种分子组合的特性，并构建功能囊泡封装浓缩蛋白质，如血红蛋白。将两端为不同头基的两亲分子通过超声分散到水中，制备了约100 nm的单分子层囊泡。通过TEM观察、囊泡总体积与计算体积的比较以及Eu^<3+>加入外水相后胆碱甲基质子峰的移位，证实了这一点。所得的囊泡非常稳定，囊泡大小没有变化，水内容物也没有泄漏。当膜的大小减小或浓缩血红蛋白被包裹时，两亲体在膜中的取向受到调节。从外水相中加入还原剂还原内氧化剂的角度分析了膜上的电子传递。将一种两端有离子基团的石胆酸衍生物掺入磷脂膜中。通过荧光脱极化法、1H-NMR和浊度测定澄清了其对分子堆积和囊泡悬浮液稳定性增强的显著影响。

Monomolecular membrane having different surface properties between inner and outer surface was prepared as vesicles. The purpose of this research is to study the characteristics of this molecular assemblies and to construct functional vesicles encapsulating concentrated protein such as hemoglobin. Amphiphilic molecules of which both ends are different head groups were dispersed into water by sonication to prepare vesicles of ca.100 nm with monomolecular layr. This was confirmed from TEM observation, the measurement of the total volume of the vesicles in comparison with calculated volume, and the shift of choline methyl proton peak in ^1H-NMR by the addition of Eu^<3+> to outer aqueous phase. The resulting vesicles were very stable, and no change of vesicular size and no leakage of aqueous contents were observed. The orientation of the amphiphiles in the membrane was regulated if the size was reduced or if concentrated hemoglobin was encapsulated. Electron transfer through the membrane was analyzed from the reduction of inner oxidants by adding reductant to the outer aqueous phase.A lithocholic acid derivatives with ionic groups at both ends was incorporated to the phospholipid membrane. A significant influence of it on the molecular packing and the stability enhancement of the vesicle suspension were clarified by a fluorescence depolarization method, 1H-NMR,and a turbidity measurement.