吐温-80与脂质体膜相互作用机理的研究

Study on the interaction mechanism between tween-80 and liposome membrane

研究了表面活性剂吐温-80(聚氧乙烯山梨醇脂肪酸酯)与脂质膜间的相互作用机理,运用浊度测定、DSC1、H—NMR等分析手段验证了脂质膜的立体稳定结构.结果表明:吐温-80在水相与脂质相间分配达到饱和时的质量浓度为1.3%,与脂质膜开始增溶成混合胶团时的质量浓度为2.6%.当Re<0.5时,表面活性剂单体在溶液和脂质双层膜中分配,溶液中表面活性剂单体和囊泡并存,脂质双层囊泡膨胀,粒径逐渐增大,形成一个肿胀的脂质囊泡.当0.5<Re<1.0时,脂质囊泡开始被表面活性剂部分增溶,成为混合胶团;当脂质双层中磷脂胆碱极性头部被其他基团所包裹,在1H—NMR和DSC相图中则观察不到胆碱头部的信号,从而表现出与普通脂质体不同的物理化学性质.

The interaction mechanism between tween-80(polyoxyethylene sorbitol fatty acid esters) and liposome membrane is studied.The structure of sterically stabilized liposome membrane is verified by some analytical means such as nephelometry,DSC,~1H-NMR and so on.The results show that tween-80 reaches to the saturation between water phase and lipid phase when the mass fraction of tween-80 is 1.3%;it begins to be solubilized into mixed colloidal mass when its mass fraction is 2.6%.When the mole ratio of tween-80 to phosphatidylcholine is 0.5,surfactant monomer coexists with vesicle,lipid bilayer vesicle dilates and its size gradually increases to become swelling lipid vesicle;when the mole ratio is between 0.5 and 1.0,lipid vesicle begins to be partly solubilized by surfactant and becomes mixed colloidal mass.When the polar head of phosphatidylcholine in lipid bilayer is surrounded by other groups,the signal of the polar head of phosphatidylcholine could not be observed in the graphs of_~1H-NMR and DSC,which is different from the physicochemical characters of general liposome.