Spontaneous Formation of Nanosized Unilamellar Polyion Complex Vesicles with Tunable Size and Properties
Spontaneous Formation of Nanosized Unilamellar Polyion Complex Vesicles with Tunable Size and Properties
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DOI：
10.1021/ja908350e
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发表时间：
2010-02-10
影响因子：
15
通讯作者：
Kataoka, Kazunori
中科院分区：
文献类型：
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作者：
Anraku, Yasutaka;Kishimura, Akihiro;Kataoka, Kazunori
通过自组装形成的具有薄且可渗透的膜的单分散、亚微米大小的囊泡（纳米体）的制造仍然是一个重大挑战。通过两亲性分子自组装制备纳米体的传统方法通常需要使用有机溶剂与物理程序（例如超声处理、热处理和膜过滤）相结合的繁琐过程，以获得具有受控尺寸分布的单层结构。在此，我们报告了通过一对带相反电荷的 PEG 嵌段异构体和同型阳离子异构体在水介质中自组装自发形成的亚微米大小的单层聚离子复合囊泡（Nano-PICsomes）的第一个例子。详细的动态光散射和透射电子显微镜分析表明，只需改变总聚合物浓度，即可将囊泡尺寸控制在 100-400 nm 范围内，且尺寸分布较窄。此外，每个 Nano-PICsome 均由均匀的单个 PIC 膜组成，无论其大小如何，其厚度约为 10-15 nm。荧光相关光谱测量证实Nano-PICsomes能够将水溶性荧光大分子封装在内水相中并缓慢释放到外部。此外，囊泡膜的交联可以调节渗透性，增强生理条件下的稳定性，并且即使在冷冻干燥和离心处理后也能保持尺寸和结构。最后，Nano-PICsomes 在小鼠血液中表现出较长的循环时间。通过简单的水自组装和通过交联轻松改变其性能来精确控制空心胶囊的粒径和结构，在生态、低成本和低能耗的制造工艺以及在生物医学领域的潜在实用性方面是相当新颖和令人着迷的。
Fabrication of monodispersed, submicrometer-sized vesicles (nanosomes) that form through self-assembly possessing a thin and permeable membrane remains a significant challenge. Conventional fabrication of nanosomes through self-assembly of amphiphilic molecules often requires cumbersome processes using organic solvents combined with physical procedures (e.g., sonication, thermal treatment, and membrane filtration) to obtain unilamellar structures with a controlled size distribution. Herein, we report the first example of spontaneously formed submicrometer-sized unilamellar polyion complex vesicles (Nano-PICsomes) via self-assembly of a pair of oppositely charged PEG block aniomer and homocatiomer in an aqueous medium. Detailed dynamic light scattering and transmission electron microscopic analysis revealed that vesicle sizes can be controlled in the range of 100-400 nm with a narrow size distribution, simply by changing the total polymer concentration. Also, each Nano-PICsome was composed of a uniform single PIC membrane, the thickness of which is around 10-15 nm, regardless of its size. Fluorescence correlation spectroscopy measurement verified that Nano-PICsomes were able to encapsulate water-soluble fluorescent macromolecules in the inner water phase and release them slowly into the exterior. Moreover, cross-linking of the vesicle membrane allows tuning of permeability, enhancement in stability under physiological conditions, and preservation of size and structure even after freeze-drying and centrifugation treatment. Finally, Nano-PICsomes showed a long circulation time in the bloodstream of mice. Precise control of the particle size and structure of hollow capsules through simple aqueous self-assembly and easy modification of their properties by cross-linking is quite novel and fascinating in terms of ecological, low-cost, and low-energy fabrication processes as well as the potential utility in the biomedical arena.