Harvey Richard D, Heenan Richard K, Barlow David J, Lawrence M Jayne
Department of Pharmacy, King's College London, Franklin Wilkins Building, 150 Stamford Street, London SE1 9NN, UK.
Chem Phys Lipids. 2005 Jan;133(1):27-36. doi: 10.1016/j.chemphyslip.2004.08.003.
Small-angle neutron-scattering (SANS) studies were performed on vesicles composed of 1,2-di-O-octadecyl-rac-glyceryl-3-(omega-methoxydodecaethylene glycol), in deuterium oxide (D2O) solutions with various ionic strengths of LiCl, NaCl and NaI. Gross vesicle morphologies, examined using freeze-fracture electron microscopy, showed that NaCl promoted the formation of multilamellar vesicles. Model fitting of the SANS data showed changes in bilayer parameters such as thickness and repeat spacings, in response to the presence of ions in the bulk solution. 2C18E12 vesicles in D2O are shown to exist as predominantly unilamellar structures with a bilayer thickness of approximately 51 A. Vesicles in increasing concentrations of LiCl and NaCl exhibit decreased layer thickness and increased lamelarity. Little change was observed for vesicles formed in NaI solutions. We suggest that these changes result from intrusion of E12 headgroups into the alkyl chain region of the vesicle bilayers, in response to the increase in concentration of ions present and their charge density.
在含有不同离子强度的LiCl、NaCl和NaI的重水溶液（D₂O）中，对由1,2 - 二 - O - 十八烷基 - rac - 甘油 - 3 -（ω - 甲氧基十二乙二醇）组成的囊泡进行了小角中子散射（SANS）研究。使用冷冻断裂电子显微镜检查的总体囊泡形态表明，NaCl促进了多层囊泡的形成。SANS数据的模型拟合显示，响应本体溶液中离子的存在，双层参数如厚度和重复间距发生了变化。D₂O中的2C18E12囊泡主要以单层结构存在，双层厚度约为51 Å。在浓度不断增加的LiCl和NaCl中形成的囊泡，其层厚度减小，层数增加。在NaI溶液中形成的囊泡几乎没有变化。我们认为，这些变化是由于E12头基侵入囊泡双层的烷基链区域，以响应存在的离子浓度及其电荷密度的增加。
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