University of Notre Dame , Department of Chemical & Biomolecular Engineering , Notre Dame , Indiana 46556 , United States.
Biomacromolecules. 2019 Dec 9;20(12):4512-4521. doi: 10.1021/acs.biomac.9b01267. Epub 2019 Nov 25.
Supramolecular hydrogels prepared from host-guest physical cross-linking of polymers have versatile utility in a number of applications. Routes to integrate stimuli-responsive features in these materials are intended to add another dimension to enhance their functionality. Herein, a guest which forms a homoternary complex with the cucurbit[8]uril macrocycle was appended to the ends of Pluronic F-127 polymers. This polymer undergoes temperature-responsive micelle formation, upon which CB[8] promotes their physical cross-linking via its host-guest interactions with the appended guests yielding a percolated hydrogel network. The particular guests used to form the homoternary complex can further be photo-dimerized to replace the physical host-guest interaction with a covalently bonded interaction. This change results in a reduction in hydrogel dynamics of roughly 2 orders of magnitude, yet temperature-responsive gelation and overall network architecture remain apparently unchanged. Hydrogels composed of micelles cross-linked by both supramolecular and photo-dimerized interactions support the injection and encapsulation of cells and enable inclusion and release of macromolecular payloads in vitro and in vivo. Thus, this approach points to a strategy to integrate external stimuli into supramolecular hydrogels through a combination of responsive polymers and light-directed supramolecular motifs.
由聚合物主客体物理交联制备的超分子水凝胶在许多应用中具有多种用途。将响应性特征集成到这些材料中的途径旨在增加另一个维度来增强其功能。本文中，一种与葫芦[8]脲大环形成同三聚体复合物的客体被连接到 Pluronic F-127 聚合物的末端。该聚合物在温度响应性胶束形成时经历相转变，其中 CB[8]通过与附加客体的主客体相互作用促进其物理交联，从而得到一个渗透的水凝胶网络。用于形成同三聚体复合物的特定客体可以进一步光二聚化，用共价键合的相互作用取代物理主客体相互作用。这种变化导致水凝胶动力学降低约 2 个数量级，但温度响应性凝胶化和整体网络结构显然保持不变。由通过超分子和光二聚化相互作用交联的胶束组成的水凝胶支持细胞的注入和封装，并能够在体外和体内包含和释放大分子有效载荷。因此，该方法为通过响应性聚合物和光导向超分子基元的组合将外部刺激整合到超分子水凝胶中提供了一种策略。
