Straubinger R M, Düzgünes N, Papahadjopoulos D
FEBS Lett. 1985 Jan 1;179(1):148-54. doi: 10.1016/0014-5793(85)80210-6.
Negatively charged liposomes are endocytosed by the coated vesicle system and accumulate in acidic intracellular vesicles. Liposomes that become unstable at acidic pH improve cytoplasmic delivery of membrane-impermeant macromolecules such as calcein (CAL) and FITC dextran (18 or 40 kDa). Oleic acid (OA): phosphatidylethanolamine (PE) (3:7 mole ratio) liposomes become permeable to CAL at pH less than 7.0. Control liposomes of phosphatidylserine:PE or OA:phosphatidylcholine are stable at pH 4-8. OA:PE liposomes promote cytoplasmic delivery of encapsulated CAL to CV-1 cells, as evidenced by the emergence of diffuse, cytoplasmic CAL fluorescence. Delivery requires metabolic energy and is partially inhibited by chloroquine or monensin, which raise the pH of intracellular vesicles.
带负电荷的脂质体通过被膜小泡系统进行内吞，并积聚在酸性细胞内小泡中。在酸性pH值下变得不稳定的脂质体可改善膜不透性大分子如钙黄绿素（CAL）和异硫氰酸荧光素葡聚糖（18或40 kDa）的细胞质递送。油酸（OA）：磷脂酰乙醇胺（PE）（摩尔比3:7）脂质体在pH值小于7.0时对CAL具有通透性。磷脂酰丝氨酸：PE或OA：磷脂酰胆碱的对照脂质体在pH 4-8时稳定。OA：PE脂质体促进包封的CAL向CV-1细胞的细胞质递送，弥漫性细胞质CAL荧光的出现证明了这一点。递送需要代谢能量，并且部分受到氯喹或莫能菌素的抑制，这两种物质会提高细胞内小泡的pH值。
