The Center for Chemical Biology, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Langmuir. 2011 Aug 2;27(15):9576-82. doi: 10.1021/la201500b. Epub 2011 Jul 6.
We created a free-standing membrane as a novel bioscaffold through the assembly of polymer-coated liposomes. Polyarginine (P(Arg)) possessing a cell-penetrating activity was used to form the polymer layer onto a negatively charged liposome (lipo-P(Arg)). The capsule wall of P(Arg) over liposomes made it possible to improve the mechanical property of capsules and to display deoxyribonucleic acid (DNA) over the vesicle surface through the electrostatic attraction (lipo-P(Arg)-DNA). The release rates of a fluorescent probe encapsulated in lipo-P(Arg) and lipo-P(Arg)-DNA were tunable by the number of polymeric layers of the capsule walls. To investigate the cell-membrane permeability of lipo-P(Arg)-DNA, polymer-coated liposomes were incubated with human umbilical vein endothelial cells (HUVECs) at 4 °C. It was found that lipo-P(Arg) underwent a significant cellular uptake, whereas bare liposomes and liposomes modified with chitosan were incapable of overcoming the plasma membrane barrier. To prepare a free-standing membrane composed of polymer-coated liposomes, a suspension of lipo-P(Arg)-DNA was cast over a mesh hole and dried up. SEM observation revealed that a free-standing membrane was obtained through drying-mediated assembly process without rupturing polymer-coated liposomes inside the membrane. On the other hand, it was not possible to obtain a complete membrane from a mixture of lipo-P(Arg) and DNA. In summary, lipo-P(Arg)-DNA capsules possess versatile functions as a drug carrier, and their assembly enables us to create a free-standing membrane applicable as a bioscaffold.
我们通过聚合物包裹的脂质体组装创建了一个独立的膜作为新型生物支架。具有细胞穿透活性的聚精氨酸（P(Arg)）被用来在带负电荷的脂质体（脂质体-P(Arg)）上形成聚合物层。脂质体-P(Arg)上的胶囊壁使胶囊的机械性能得以提高，并通过静电吸引在囊泡表面显示脱氧核糖核酸（DNA）（脂质体-P(Arg)-DNA）。通过胶囊壁的聚合物层的数量可以调节封装在脂质体-P(Arg)和脂质体-P(Arg)-DNA 中的荧光探针的释放速率。为了研究脂质体-P(Arg)-DNA 的细胞膜通透性，聚合物包裹的脂质体在 4°C 下与人脐静脉内皮细胞（HUVECs）孵育。结果发现，脂质体-P(Arg) 经历了显著的细胞摄取，而裸露的脂质体和用壳聚糖修饰的脂质体则无法克服质膜屏障。为了制备由聚合物包裹的脂质体组成的独立膜，将脂质体-P(Arg)-DNA 的悬浮液浇铸在网格孔上并干燥。SEM 观察表明，通过干燥介导的组装过程获得了独立的膜，而不会破坏膜内的聚合物包裹的脂质体。另一方面，从脂质体-P(Arg) 和 DNA 的混合物中不可能获得完整的膜。总之，脂质体-P(Arg)-DNA 囊泡作为药物载体具有多种功能，它们的组装使我们能够创建适用于生物支架的独立膜。
