Amphiphilic ureas with hydrophilic lactose groups form transparent supramolecular hydrogels. Their gelation abilities are sensitive to the length of the alkyl chain. Amphiphilic ureas bearing hexyl, heptyl, octyl, and nonyl groups form supramolecular hydrogels, but amphiphilic ureas bearing decyl groups or longer alkyl groups do not show gelation ability. The gradual gel-to-sol phase transition of the supramolecular hydrogel is triggered by adding β-galactosidase (β-Gal) as a result of enzymatic hydrolysis of the lactose moiety. Supramolecular hydrogels could stably entrap cationic organic dyes, such as rhodamine 6G (Rh6G), even in water. The entrapped Rh6G could be gradually released in the presence of β-Gal, along with the gel-to-sol phase transition. Lactose-coupled amphiphilic ureas are worked as low-molecular-weight hydrogelators (LMWHGs). Their gelation abilities are sensitive to the length of the hydrophobic alkyl chain. Gradual gel-to-sol phase transition of the supramolecular hydrogel was occurred by adding β-galactosidase (β-Gal) as a result of enzymatic hydrolysis of the lactose moiety. Supramolecular hydrogels could stably entrap cationic organic dyes even in water. The entrapped dye could be gradually released in the presence of β-Gal, along with the gel-to-sol phase transition.

中文翻译：

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两亲性尿素超分子水凝胶的酶响应特性

具有亲水性乳糖基团的两亲性脲形成透明的超分子水凝胶。它们的胶凝能力对烷基链的长度很敏感。带有己基、庚基、辛基和壬基的两亲脲形成超分子水凝胶，但带有癸基或更长烷基的两亲脲不显示凝胶化能力。由于乳糖部分的酶促水解，通过添加 β-半乳糖苷酶 (β-Gal) 触发超分子水凝胶的逐渐凝胶到溶胶相变。超分子水凝胶即使在水中也能稳定捕获阳离子有机染料，如罗丹明 6G (Rh6G)。在 β-Gal 存在的情况下，随着凝胶到溶胶的相变，捕获的 Rh6G 可以逐渐释放。乳糖偶联的两亲性尿素用作低分子量水凝胶剂 (LMWHG)。它们的胶凝能力对疏水烷基链的长度很敏感。由于乳糖部分的酶促水解，通过添加 β-半乳糖苷酶 (β-Gal) 发生超分子水凝胶的逐渐凝胶到溶胶相变。超分子水凝胶即使在水中也能稳定捕获阳离子有机染料。在 β-Gal 存在的情况下，随着凝胶到溶胶的相变，捕获的染料可以逐渐释放。