Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Republic of Korea.
Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, 130-650, Republic of Korea.
Mater Sci Eng C Mater Biol Appl. 2019 Feb 1;95:86-94. doi: 10.1016/j.msec.2018.10.045. Epub 2018 Oct 11.
Human skin exhibits high stiffness of up to 100 MPa and high toughness of up to 3600 J m despite its high water content of 40-70 wt%. Engineering hydrogels have rarely possessed both high stiffness and toughness, because compliant hydrogels usually become brittle when excess crosslinker is added to make the gel stiff. Furthermore, conventional hydrogels usually swell under physiological conditions, weakening their mechanical properties. Here, we designed a non-swellable hydrogel with high stiffness and toughness by interpenetrating covalently and ionically crosslinked networks. The stiffness is enhanced by utilizing ionic crosslinking sites fully, and the toughness is enhanced by adopting synergistic effects between energy-dissipation by ionic networks and crack-bridging by covalent networks. Non-swelling behaviors of the gel are achieved by densifying covalent and ionic crosslinks. The hybrid gel shows high elastic moduli (up to 108 MPa) and high fracture energies (up to 8850 J m). In vitro and in vivo swelling tests prove non-swelling behaviors of the gel. Live/dead assays show 99% cell viability over a period of 60 days.
尽管人体皮肤的含水量高达 40-70wt%，但其硬度可高达 100MPa，韧性可高达 3600J/m。工程水凝胶很少同时具备高硬度和韧性，因为当添加过多的交联剂以使水凝胶变硬时，柔软的水凝胶通常会变得易碎。此外，传统的水凝胶通常在生理条件下会发生溶胀，从而削弱其机械性能。在这里，我们通过共价和离子交联网络的互穿设计了一种具有高硬度和韧性的不可溶胀水凝胶。通过充分利用离子交联位点来提高硬度，通过采用离子网络耗散能量和共价网络桥接裂纹的协同效应来提高韧性。通过致密化共价和离子交联来实现凝胶的非溶胀行为。该杂化凝胶表现出高弹性模量（高达 108MPa）和高断裂能（高达 8850J/m）。体外和体内溶胀试验证明了该凝胶的非溶胀行为。活/死试验表明，在 60 天的时间内，细胞存活率达到 99%。
