标题： DNA的包封由阳离子二嵌段共聚物囊泡 显示英文标题

标题： Encapsulation of DNA by cationic diblock copolymer vesicles

摘要： 通过阳离子二嵌段共聚物聚(丁二烯-b-N-甲基4-乙烯基吡啶)[PBd-b-P4VPQ]对dsDNA片段(轮廓长度54 nm)的包封已被研究，使用了相衬、偏光和荧光显微镜以及扫描电子显微镜。通过单乳液技术实现了包封。为此，将水相DNA溶液在有机溶剂(甲苯)中乳化，并由两亲性二嵌段共聚物稳定。PBd段形成界面刷，而阳离子P4VPQ段与DNA复合。随后改变有机溶剂的质量导致PBd刷的坍塌和胶囊的形成。在胶囊内，DNA被压缩，这由交叉偏振器下双折射纹理的出现和标记DNA的荧光强度的增加所显示。如果在外部相中用渗透压剂(聚乙二醇)稳定胶囊，它们也可以分散在水介质中以形成囊泡。结果表明，一旦渗透压低于105 N/m2或支持介质的离子强度超过0.1 M，DNA就会从囊泡中释放出来。该方法还证明可以有效地将pUC18质粒包封在亚微米大小的囊泡中，并且通过制备电荷相反系统:阳离子聚(乙烯亚胺)被阴离子二嵌段聚(苯乙烯-b-丙烯酸)包封，展示了该方法的一般适用性。 显示英文摘要

摘要： Encapsulation of dsDNA fragments (contour length 54 nm) by the cationic diblock copolymer poly(butadiene-b-N-methyl 4-vinyl pyridinium) [PBd-b-P4VPQ] has been studied with phase contrast, polarized light, and fluorescence microscopy, as well as scanning electron microscopy. Encapsulation was achieved with a single emulsion technique. For this purpose, an aqueous DNA solution is emulsified in an organic solvent (toluene) and stabilized by the amphiphilic diblock copolymer. The PBd block forms an interfacial brush, whereas the cationic P4VPQ block complexes with DNA. A subsequent change of the quality of the organic solvent results in a collapse of the PBd brush and the formation of a capsule. Inside the capsules, the DNA is compacted as shown by the appearance of birefringent textures under crossed polarizers and the increase in fluorescence intensity of labeled DNA. The capsules can also be dispersed in aqueous medium to form vesicles, provided they are stabilized with an osmotic agent (polyethylene glycol) in the external phase. It is shown that the DNA is released from the vesicles once the osmotic pressure drops below 105 N/m2 or if the ionic strength of the supporting medium exceeds 0.1 M. The method has also proven to be efficient to encapsulate pUC18 plasmid in sub-micron sized vesicles and the general applicability of the method has been demonstrated by the preparation of the charge inverse system: cationic poly(ethylene imine) encapsulated by the anionic diblock poly(styrene-b-acrylic acid).