Enthalpic incompatibility between two steric stabilizer blocks provides control over the vesicle size distribution during polymerization-induced self-assembly in aqueous media.
Enthalpic incompatibility between two steric stabilizer blocks provides control over the vesicle size distribution during polymerization-induced self-assembly in aqueous media.
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DOI：
10.1039/d0sc01320j
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发表时间：
2020-10-21
期刊：
影响因子：
8.4
通讯作者：
Armes SP
中科院分区：
文献类型：
--
作者：
Beattie DL;Mykhaylyk OO;Armes SP
SAXS的研究证实，一个明智的二元混合物的手性不相容的空间稳定剂块，使合成相对较小的，明确定义的囊泡通过聚合诱导的自组装在水性介质中。在过去的二十年中，嵌段共聚物囊泡已被许多研究小组广泛用于包封小分子药物、遗传物质、纳米颗粒或酶。它们也被用于设计自主自推进纳米粒子的例子。传统上，这样的囊泡通过使用水混溶性共溶剂如DMF或THF的后聚合处理来制备。然而，这样的方案总是在稀溶液中进行，这是一个显著的缺点。此外，囊泡尺寸分布通常相当宽，而具有窄尺寸分布的相对小的囊泡的水性分散体对于潜在的生物医学应用是高度期望的。或者，嵌段共聚物囊泡的浓缩分散体可以通过聚合诱导的自组装（比萨）直接制备。此外，使用相对长和相对短的空间稳定剂嵌段的二元混合物能够方便地合成在醇介质中具有合理窄的尺寸分布的相对小的囊泡的比萨（C. Gonzato等人，JACS，2014，136，11100-11106）。不幸的是，这种方法尚未被证明用于水性介质，这对于商业应用将更具吸引力。在这里，我们表明，这一重要的技术目标可以通过明智地使用两种化学上不同的，在物理上不相容的空间稳定剂块，这确保了所需的微相分离的囊泡膜。通过透射电子显微镜、动态光散射和小角度X射线散射判断，这导致在10%w/w固体的水性介质中形成约200 nm直径（尺寸多分散性= 13-16%）的良好限定的囊泡。
SAXS studies confirm that a judicious binary mixture of enthalpically incompatible steric stabilizer blocks enables the synthesis of relatively small, well-defined vesicles via polymerization-induced self-assembly in aqueous media. Over the past two decades, block copolymer vesicles have been widely used by many research groups to encapsulate small molecule drugs, genetic material, nanoparticles or enzymes. They have also been used to design examples of autonomous self-propelled nanoparticles. Traditionally, such vesicles are prepared via post-polymerization processing using a water-miscible co-solvent such as DMF or THF. However, such protocols are invariably conducted in dilute solution, which is a significant disadvantage. In addition, the vesicle size distribution is often quite broad, whereas aqueous dispersions of relatively small vesicles with narrow size distributions are highly desirable for potential biomedical applications. Alternatively, concentrated dispersions of block copolymer vesicles can be directly prepared via polymerization-induced self-assembly (PISA). Moreover, using a binary mixture of a relatively long and a relatively short steric stabilizer block enables the convenient PISA synthesis of relatively small vesicles with reasonably narrow size distributions in alcoholic media (C. Gonzato et al., JACS, 2014, 136, 11100–11106). Unfortunately, this approach has not yet been demonstrated for aqueous media, which would be much more attractive for commercial applications. Herein we show that this important technical objective can be achieved by judicious use of two chemically distinct, enthalpically incompatible steric stabilizer blocks, which ensures the desired microphase separation across the vesicle membrane. This leads to the formation of well-defined vesicles of around 200 nm diameter (size polydispersity = 13–16%) in aqueous media at 10% w/w solids as judged by transmission electron microscopy, dynamic light scattering and small-angle X-ray scattering.
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影响因子：
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