Recent developments in the field of polymer vesicles, i.e. polymersomes, have demonstrated that disrupting the equilibrium conditions of the milieu could lead to shape transformation into stable non-spherical morphologies, bringing on-demand shape control to reality and bearing great promise for cell mimicry and a variety of biomedical applications. Here, we studied the self-assembly behavior of glassy amphiphilic triblock copolymers, poly(ethylene glycol)-block-polystyrene-stat-poly(coumarin methacrylate)-block-poly(ethylene glycol) (PEG-b-P(S-stat-CMA)-b-PEG), and their response to various stimuli. By changing the respective molecular weights of both the hydrophobic P(S-stat-CMA) and the hydrophilic PEG blocks, we varied the hydrophobic volume fraction thereby accessing a range of morphologies from spherical and worm-like micelles, as well as polymersomes. For the latter, we observed that slow osmotic pressure changes induced by dialysis led to a decrease in size while rapid osmotic pressure changes by addition of a PEG fusogen led to morphological transformations into rod-like and tubular polymersomes. We also found out that chemically crosslinking the vesicles before inducing osmotic pressure changes led to the vesicles exhibiting hypotonic shock, atypical for glassy polymersomes. We believe that this approach combining the robustness of triblock copolymers and light-based transformations will help expand the toolbox to design ever more complex biomimetic constructs.

中文翻译：

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由玻璃状和可交联的ABA三嵌段共聚物对聚合物囊泡进行形变

聚合物囊泡（即聚合物小体）领域的最新发展表明，破坏环境的平衡条件可能导致形状转换为稳定的非球形形态，使按需形状控制成为现实，并为细胞模拟和应用带来了广阔前景多种生物医学应用。在这里，我们研究了两亲性的玻璃状的三嵌段共聚物，聚（乙二醇）的自组装行为-块-polystyrene- STAT -聚（甲基丙烯酸香豆素） -嵌段-聚（乙二醇）（PEG- b -P（S- STAT -CMA）-b-PEG），以及它们对各种刺激的反应。通过改变两种疏水性P（S- stat-CMA）和亲水性PEG嵌段，我们改变了疏水性体积分数，从而获得了球形和蠕虫状的胶束以及聚合物小体的一系列形态。对于后者，我们观察到由透析引起的缓慢的渗透压变化导致尺寸减小，而通过添加PEG融合剂引起的快速渗透压变化导致形态转化为棒状和管状聚合物囊泡。我们还发现，在诱导渗透压变化之前化学交联囊泡会导致囊泡表现出低渗性休克，这对于玻璃状聚合物囊泡而言是非典型的。我们相信，这种结合了三嵌段共聚物的耐用性和基于光的转化的方法将有助于扩展工具箱，以设计越来越复杂的仿生构造。