pH-Responsive shrinkage/swelling of a supramolecular hydrogel composed of two small amphiphilic molecules.
pH-Responsive shrinkage/swelling of a supramolecular hydrogel composed of two small amphiphilic molecules.
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DOI：
10.1002/chem.200400677
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
Shan-Lai Zhou;S. Matsumoto;Hua Tian;Hiroki Yamane;A. Ojida;Shigeki Kiyonaka;I. Hamachi
中科院分区：
文献类型：
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作者：
Shan-Lai Zhou;S. Matsumoto;Hua Tian;Hiroki Yamane;A. Ojida;Shigeki Kiyonaka;I. Hamachi
通过将其与适量的 2a 或 2b 两亲性羧酸简单混合，成功地将 pH 响应体积变化功能引入到含有 GalNAc 附加（GalNAc=N-乙酰半乳糖胺）谷氨酸酯 1 的超分子水凝胶中。在 1:1 混合物 (1:2) 中，水凝胶在中性 pH 条件下膨胀，但在酸性 pH 条件下收缩至其原始体积的几乎一半。通过使用 X 射线衍射 (XRD)、共焦激光扫描显微镜 (CLSM)、透射或扫描电子显微镜 (TEM、SEM) 和傅里叶变换红外 (FTIR) 光谱来表征混合水凝胶的结构和 pH 响应。发育良好的纤维通过自组装形成稳定的水凝胶，在酸性条件下，羧酸末端（来自羧酸根阴离子）的电荷被中和，然后这些纤维变得致密。这种宏观 pH 响应也适用于 pH 触发的生物活性物质的释放。在这种混合超分子水凝胶中，水凝胶剂1提供稳定的水凝胶结构，添加剂2充当对环境pH信号敏感的指挥器。目前的超分子共聚策略应可用于构建新型的刺激响应性软材料。
A pH-responsive volume-change function was successfully introduced into a supramolecular hydrogel that contained GalNAc-appended (GalNAc=N-acetylgalactosamine) glutamate ester 1 by the simple mixing of it with an appropriate amount of 2 a or 2 b amphiphilic carboxylic acid. In the 1:1 mixture (1:2), the hydrogel swelled under neutral pH conditions, but shrank to almost half of its original volume under acidic pH conditions. The structure and pH response of the mixed hydrogel were characterized by using X-ray diffraction (XRD), confocal laser scanning microscopy (CLSM), transmission or scanning electron microscopy (TEM, SEM), and Fourier transform IR (FTIR) spectroscopy. Well-developed fibers formed a stable hydrogel by self-assembly, and under acidic conditions the charge of the carboxylic acid terminal (from the carboxylate anion) was neutralized and then these fibers became densely packed. This macroscopic pH response was also applied to the pH-triggered release of bioactive substances. In this mixed supramolecular hydrogel, the hydrogelator 1 provides a stable hydrogel structure and the additive 2 acts as a commander that is sensitive to an environmental pH signal. The present supramolecular copolymerization strategy should be useful for the construction of novel, stimuli-responsive, soft materials.