Supramolecular hydrogels formed by noncovalent bonds are attractive “smart” materials, which can rapidly respond to external stimuli. However, only a handful of supramolecular hydrogels is applicable in tissue engineering, due to the instability and poor mechanical strength of noncovalent cross-linking hydrogels. Thus, a rigid and stable supramolecular hydrogel has been developed based on poly(l-glutamic acid) and 2-ureido-4[1H]pyrimidinones (UPy), and the UPy stacks are noncovalent cross-linking interactions. The hydrogels show excellent mechanical strength and stability, in sharp contrast to noncovalent hydrogels cross-linked by UPy dimers and covalent hydrogels cross-linked by esterification. The hydrogels also exhibit remoldability, self-healing, and thermoplastic printing characteristics, which are caused by the reversible supramolecular property of UPy stacks. Also, the formation of hydrogels dependent on UPy stacks is further investigated by atomic force microscope, small-angle X-ray scattering, in situ X-ray diffraction, circular dichroism, and UV–vis spectroscopies. Finally, the hydrogels show commendable biocompatibility and degradability, which have high potential applications in regenerative medicine.

中文翻译：

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具有机械增强性，高稳定性，自修复性和聚（1-谷氨酸）和脲基-嘧啶酮的热塑性的基于堆栈的水凝胶

由非共价键形成的超分子水凝胶是有吸引力的“智能”材料，可以快速响应外部刺激。但是，由于非共价交联水凝胶的不稳定性和较差的机械强度，因此仅有极少数的超分子水凝胶可用于组织工程。因此，已经开发了基于聚（1-谷氨酸）和2-脲基-4 [ 1H]的刚性和稳定的超分子水凝胶。] pyrimidinones（UPy）和UPy堆栈是非共价交联相互作用。与通过UPy二聚体交联的非共价水凝胶和通过酯化交联的共价水凝胶形成鲜明对比的是，水凝胶显示出优异的机械强度和稳定性。水凝胶还显示出可重塑性，自修复性和热塑性印刷特性，这是由UPy叠层的可逆超分子性质引起的。另外，通过原子力显微镜，小角度X射线散射，原位X射线衍射，圆二色性和UV-vis光谱学进一步研究了取决于UPy叠层的水凝胶的形成。最后，水凝胶显示出值得称赞的生物相容性和可降解性，在再生医学中具有很高的潜在应用价值。