Loading of Silica Nanoparticles in Block Copolymer Vesicles during Polymerization-Induced Self-Assembly: Encapsulation Efficiency and Thermally Triggered Release.
Loading of Silica Nanoparticles in Block Copolymer Vesicles during Polymerization-Induced Self-Assembly: Encapsulation Efficiency and Thermally Triggered Release.
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DOI：
10.1021/jacs.5b10415
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发表时间：
2015-12-30
影响因子：
15
通讯作者：
Armes SP
中科院分区：
文献类型：
--
作者：
Mable CJ;Gibson RR;Prevost S;McKenzie BE;Mykhaylyk OO;Armes SP
聚甲基丙烯酸甘油单酯-聚甲基丙烯酸羟丙酯两嵌段共聚物微囊可通过聚合诱导自组装(PISA)以浓缩水分散体的形式制备。在本研究中，这些合成是在直径约18 nm的不同数量的二氧化硅纳米颗粒存在的情况下进行的。这种方法导致每个囊泡包裹多达数百个二氧化硅纳米颗粒。与共聚物相比，二氧化硅具有更高的电子对比度，这有助于进行透射电子显微镜分析，并且其热稳定性使其能够通过热重分析来量化负载效率。包封率可以用圆盘离心光散射测定法计算，因为在较高的二氧化硅负载量下，囊泡密度增加，而平均囊泡直径基本保持不变。由于在Q≈为0.25 nm-1处观察到一个结构因子，因此用小角X射线散射证实了二氧化硅的包覆。一个新的二布居模型提供了令人满意的数据拟合小角X射线散射图，并允许确定囊泡中二氧化硅的平均体积分数。最后，两嵌段共聚物微囊的热响应性使得只需冷却到0-10°C即可通过热触发释放包裹的二氧化硅纳米颗粒，这会导致形态转变。这些二氧化硅负载的囊泡构成了一个有用的模型系统，用于理解球形蛋白质、酶或抗体的包裹，以用于潜在的生物医学应用。它们也可以作为自我修复水凝胶或修复生物组织的有效载荷。最后，我们还封装了一个模型球状蛋白--牛血清白蛋白，并用荧光光谱计算了它的负载效率。
Poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) diblock copolymer vesicles can be prepared in the form of concentrated aqueous dispersions via polymerization-induced self-assembly (PISA). In the present study, these syntheses are conducted in the presence of varying amounts of silica nanoparticles of approximately 18 nm diameter. This approach leads to encapsulation of up to hundreds of silica nanoparticles per vesicle. Silica has high electron contrast compared to the copolymer which facilitates TEM analysis, and its thermal stability enables quantification of the loading efficiency via thermogravimetric analysis. Encapsulation efficiencies can be calculated using disk centrifuge photosedimentometry, since the vesicle density increases at higher silica loadings while the mean vesicle diameter remains essentially unchanged. Small angle X-ray scattering (SAXS) is used to confirm silica encapsulation, since a structure factor is observed at q ≈ 0.25 nm–1. A new two-population model provides satisfactory data fits to the SAXS patterns and allows the mean silica volume fraction within the vesicles to be determined. Finally, the thermoresponsive nature of the diblock copolymer vesicles enables thermally triggered release of the encapsulated silica nanoparticles simply by cooling to 0–10 °C, which induces a morphological transition. These silica-loaded vesicles constitute a useful model system for understanding the encapsulation of globular proteins, enzymes, or antibodies for potential biomedical applications. They may also serve as an active payload for self-healing hydrogels or repair of biological tissue. Finally, we also encapsulate a model globular protein, bovine serum albumin, and calculate its loading efficiency using fluorescence spectroscopy.