液晶态磷脂酰乙醇胺脂质体和LB膜结构的研究

用原子力显微镜、小角X射线散射和³¹PNMR分别对液晶态磷脂酰乙醇胺脂质体和LB膜结构进行了研究.用原子力显微镜观察到了液晶态脂质体的立方相和双层膜共存的结构图像.研究结果表明,两相共存的状态与双亲性分子的结构、浓度以及介质的组分和pH等因素有关.用小角X射线散射和³¹PNMR研究发现,在DEPE液晶态中,钠盐诱导形成Q²²⁹(Im3m)立方相.DEPE液晶态分别在37.5℃出现L_β→L_α可逆相变,在63.5℃出现L_α→H_Ⅱ可逆相变.

Structure of Phosphatidylethanolamine Liposome and Langmuir-Blodgett Films in Liquid Crystalline State

The structure of phosphatidylethanolamine in Langmuir-Blodgett films and liposome in liquid crystalline state was investigated by means of the atomic force microscope(AFM), small angle X-ray scatting(SAXS) and 31P nuclear magnetism resonance( 31P NMR). By the atomic force microscope, some large and small lipid vesicles and a coexistent structure of cubic phase and bilayer phase of PE liposome were observed. The coexistent structure of the two phases is closely related to the structure of phospholipid, concentration, medium and pH. It was found that sodium salt solutes induce the formation of an Im3m(Q229) cubic phase in DEPE dispersions. The phase transition of DEPE with the change of temperature was investigated. The Lβ→Lα transitions are at 37.5 ℃ and the Lα→HⅡ transitions are at 63.5 ℃.