Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
J Am Chem Soc. 2010 Mar 24;132(11):3654-5. doi: 10.1021/ja910606y.
Polymer vesicles, or polymersomes, are promising candidates for applications in drug delivery and tissue imaging. While a vast variety of polymers have been explored for their ability to assemble into polymersomes, relatively little research on the functionalization of these polymers has been reported. We present here a novel route for the synthesis of poly(caprolactone)-b-poly(ethylene glycol) (PCL-b-PEG) diblock copolymers that allows for the insertion of functional groups at the block junctions and the assembly of functional membranes. This modular synthesis has been developed on the basis of solid-phase peptide synthesis techniques and is accomplished through the formation of two peptide bonds, one between an amine-terminated PEG and the carboxyl moiety of the functional group and the other between the functional group amine and a carboxy-terminated PCL. As a demonstration of the potential utility of the resulting vesicles, we incorporated two different amino acid functional groups at the junction. 2-Nitrophenylalanine was utilized to create UV-responsive membranes in which the vesicles were destabilized and released encapsulated contents upon irradiation. A fluorescein-conjugated lysine was also utilized to create stable fluorescent membranes in which the fluorescence was built into the polymer. This method should contribute to our ability to further develop smart, functional membranes.
聚合物囊泡，或聚合物胶束，是药物输送和组织成像应用的有前途的候选物。虽然已经探索了大量的聚合物，以研究它们组装成聚合物胶束的能力，但对这些聚合物的功能化研究相对较少。我们在这里提出了一种合成聚己内酯-b-聚乙二醇（PCL-b-PEG）两亲嵌段共聚物的新途径，该途径允许在嵌段连接处插入功能基团，并组装功能性膜。这种模块化合成是基于固相肽合成技术开发的，通过形成两个肽键来完成，一个是在氨基末端的 PEG 和功能基团的羧基部分之间，另一个是在功能基团的氨基和羧基末端的 PCL 之间。作为对所得囊泡潜在用途的证明，我们在连接处引入了两种不同的氨基酸功能基团。利用 2-硝基苯丙氨酸来制备对紫外光有响应的膜，其中囊泡在照射时不稳定并释放包封的内容物。还利用荧光素标记的赖氨酸来制备稳定的荧光膜，其中荧光被嵌入聚合物中。这种方法应该有助于我们进一步开发智能、功能性膜的能力。
