Wang Qi, Shi Zhen, Shou Yufeng, Zhang Kunxi, Li Guifei, Xia Pengfei, Yan Shifeng, Yin Jingbo
Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, No. 99 Shangda Road, Shanghai 200444, P. R. China.
ACS Biomater Sci Eng. 2020 Mar 9;6(3):1715-1726. doi: 10.1021/acsbiomaterials.0c00010. Epub 2020 Feb 3.
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[1]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.
由非共价键形成的超分子水凝胶是具有吸引力的“智能”材料，能够快速响应外部刺激。然而，由于非共价交联水凝胶的不稳定性和较差的机械强度，仅有少数超分子水凝胶可应用于组织工程。因此，基于聚（L-谷氨酸）和2-脲基-4[1]嘧啶酮（UPy）开发了一种刚性且稳定的超分子水凝胶，且UPy堆叠为非共价交联相互作用。与由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，该水凝胶表现出优异的机械强度和稳定性。该水凝胶还具有可重塑性、自愈性和热塑性打印特性，这些特性由UPy堆叠的可逆超分子性质引起。此外，通过原子力显微镜、小角X射线散射、原位X射线衍射、圆二色性和紫外可见光谱对依赖UPy堆叠的水凝胶形成进行了进一步研究。最后，该水凝胶表现出良好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。
