Supramolecular Hydrogels via Light-Responsive Homoternary Cross-Links
Supramolecular Hydrogels via Light-Responsive Homoternary Cross-Links
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DOI：
10.1021/acs.biomac.0c00950
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发表时间：
2021-01-01
影响因子：
6.2
通讯作者：
Webber, Matthew J.
中科院分区：
文献类型：
--
作者：
Zou, Lei;Addonizio, Christopher J.;Webber, Matthew J.
主-客体物理交联已被用于制备用于各种生物医学应用的超分子水凝胶。最近赋予这些材料刺激响应性的努力提供了一个机会，可以精确地调整它们的功能以用于目标用途。在光响应材料的背景下，偶氮苯是一种主要的基序。在这里，探索了不对称偶氮苯与葫芦[8]脲大环化合物形成同型复合物的能力，其对于顺序结合表现出6.21 × 10（10）M-2的亲和力（K-eq），尽管具有负协同性。共聚物首先从不同的和可调比例的NIPAM和DMAEA制备，然后DMAEA基团合成后用这种不对称偶氮苯改性。大环加成后，这些聚合物形成超分子水凝胶;由于温度依赖性的三元复合物的亲和力降低，松弛动力学随温度增加。紫外光的应用破坏了超分子基序通过偶氮苯光异构化，促使凝胶到溶胶的转变的水凝胶。令人兴奋的是，在室温下几分钟内，偶氮苯的热弛豫到其反式状态提供了快速的水凝胶恢复。通过揭示这种超分子基序并采用简单的方法将其连接到预合成的聚合物上，本文所述的方法可以进一步实现对超分子水凝胶的刺激导向控制，以用于许多应用。
Host-guest physical cross-linking has been used to prepare supramolecular hydrogels for various biomedical applications. More recent efforts to endow these materials with stimuli-responsivity offers an opportunity to precisely tune their function for a target use. In the context of light-responsive materials, azobenzenes are one prevailing motif. Here, an asymmetric azobenzene was explored for its ability to form homoternary complexes with the cucurbit[8]uril macrocyde, exhibiting an affinity (K-eq) of 6.21 x 10(10) M-2 for sequential binding, though having negative cooperativity. Copolymers were first prepared from different and tunable ratios of NIPAM and DMAEA, and DMAEA groups were then postsynthetically modified with this asymmetric azobenzene. Upon macrocyde addition, these polymers formed supramolecular hydrogels; relaxation dynamics increased with temperature due to temperature-dependent affinity reduction for the ternary complex. Application of UV light disrupted the supramolecular motif through azobenzene photoisomerization, prompting a gel-to-sol transition in the hydrogel. Excitingly, within several minutes at room temperature, thermal relaxation of azobenzene to its trans state afforded rapid hydrogel recovery. By revealing this supramolecular motif and employing facile means for its attachment onto pre-synthesized polymers, the approach described here may further enable stimuli-directed control of supramolecular hydrogels for a number of applications.