Block copolymer self-assembly in solution

嵌段共聚物囊泡(BCV)是由两亲两嵌段共聚物在溶液中制备的空心球。它们的大小从大约100纳米到大约1000纳米，壁厚大约20纳米。在早期的工作中，我们已经证明了通过控制制备条件可以非常容易地制备嵌段共聚聚合物囊泡。它们是形态连续体的一部分，形态连续体包括球形胶束和棒状物。与脂质体一样，BCVs在药理学(药物输送)、化妆品和催化等领域有着潜在的应用前景，但比脂质体更稳定。我们最近已经证明，许多囊泡参数，如大小和壁厚，可以由外部制备条件和聚合物组成来控制。我们还表明，一步就可以制备出具有不同内部和外部界面的囊泡。此外，我们已经证明，可以根据需要软化墙壁，允许使用阿霉素(一种抗癌药物)等成分进行活性填充，通过硬化墙壁来锁定成分，然后根据需要重新打开以释放内容物。我们还证明了通过交换内部和外部界面来颠倒囊泡是可能的。我们现在建议探索一种囊泡中的“呼吸”机制，它允许囊泡在大约1分钟内重复增加或减少体积约10倍。这将使成分的吸收和释放非常迅速。我们还学习了如何将纳米颗粒(如树枝状大分子)结合到囊壁中，现在建议系统地研究一些不同物种的包结，包括催化剂到囊壁中。此外，我们建议研究特定几何结构的物种(例如球体)加入嵌段共聚聚合物聚集体中，并研究强相互作用对所得聚集体形态发生的影响。还考虑了其他几项较小的研究，包括探索通过囊泡壁的扩散和将大分子困在囊泡的腔内。

Block copolymer vesicles (BCVs) are hollow spheres which can be prepared in solution from amphiphilic diblock copolymers. They range in size from ca. 100 to ca. 1000 nm, with a wall thickness of ca. 20 nm. In early work, we have shown that block copolymer vesicles can be prepared very easily by controlling the preparation conditions. They are part of a morphological continuum which includes spherical micelles and rods. Like liposomes, BCVs are promissing in many potential applications in fields such as pharmacology (in drug delivery), cosmetics and catalysis, but are much more stable than liposomes. We have shown recently that many vesicle parameters, such as size and wall thickness, can be controlled by external preparative conditions and polymer composition. We have also shown that it is possible to prepare, in one step, vesicles with different interior and exterior interfaces. Furthermore, we have shown that it is possible to soften the wall on demand to permit active filling with ingredients such is doxorubicin (a cancer killer), to lock in the ingredients by hardening the wall, and than to "re-open it" on demand to release the contents. We have also shown that it is possible to invert the vesicles by exchanging the interior and exterior interfaces. We now propose to explore a "breathing" mechanism in vesicles which allows them to increase or decrease their volume repeatedly by a factor of ca. 10x within ca. 1 minute. This would allow the uptake and release of ingredients very rapidly. We have also learned how to incorporate nanoparticles such as dendrimers within vesicles walls, and now propose to study systematically the inclusion of a number of different species, including catalysts into vesicle walls. In addition, we propose to examine the incorporation of species of specific geometry (e.g. spheres) into block copolymer aggregates and to study the effect of strong interactions on morphogenesis of the resulting aggregates. Several other minor studies are contemplated including the exploration of diffusion through vesicle walls and the entrapment of large molecules inside the cavities of vesicles.