State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Department of Breast Surgery, Cancer Hospital of China Medical University, Shenyang 110042, China.
ACS Nano. 2023 Jul 25;17(14):13522-13532. doi: 10.1021/acsnano.3c01976. Epub 2023 Jul 13.
Hydrogels are able to mimic the flexibility of biological tissues or skin, but they still cannot achieve satisfactory strength and toughness, greatly limiting their scope of application. Natural wood can offer inspiration for designing high-strength hydrogels attributed to its anisotropic structure. Herein, we propose an integrated strategy for efficient preparation of ultrastrong hydrogels using a salting-assisted prestretching treatment. The as-prepared poly(vinyl alcohol)/cellulose nanofiber hybrid hydrogels show distinct wood-like anisotropy, including oriented molecular fiber bundles and extended grain size, which endows materials with extraordinarily comprehensive mechanical properties of ultimate breaking strength exceeding 40 MPa, strain approaching 250%, and toughness exceeding 60 MJ·m, and outstanding tear resistance. Impressively, the breaking strength and toughness of the reswollen preoriented hydrogels approach 10 MPa and 25 MJ·m, respectively. and tests demonstrate that the reswollen hydrogels do not affect the growth and viability of the cells, nor do they cause the inflammation or rejection of the mouse tissue, implying extremely low biotoxicity and perfect histocompatibility, showcasing bright prospects for application in artificial ligaments or tendons. The strategy provided in this study can be generalized to a variety of biocompatible polymers for the fabrication of high-performance hydrogels with anisotropic structures.
水凝胶能够模拟生物组织或皮肤的柔韧性，但它们仍然无法达到令人满意的强度和韧性，极大地限制了它们的应用范围。天然木材的各向异性结构为设计高强度水凝胶提供了灵感。在此，我们提出了一种使用盐辅助预拉伸处理来高效制备超强度水凝胶的综合策略。所制备的聚乙烯醇/纤维素纳米纤维杂化水凝胶表现出明显的木材状各向异性，包括定向的分子纤维束和扩展的晶粒尺寸，赋予材料具有非凡的综合机械性能，其极限断裂强度超过 40 MPa，应变接近 250%，韧性超过 60 MJ·m-3，并且具有出色的抗撕裂性。令人印象深刻的是，再溶胀预定向水凝胶的断裂强度和韧性分别达到 10 MPa 和 25 MJ·m-3。细胞增殖和活力测试表明，再溶胀水凝胶不会影响细胞的生长和活力，也不会引起小鼠组织的炎症或排斥反应，这意味着极低的生物毒性和完美的组织相容性，展示了在人工韧带或肌腱中的应用前景。本研究中提供的策略可以推广到多种生物相容性聚合物，用于制备具有各向异性结构的高性能水凝胶。
