State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , 5625 Renmin Street , Changchun 130022 , P. R. China.
College of Applied Chemistry and Engineering , University of Science and Technology of China , Jinzhai Road No 96 , Hefei 230026 , P. R. China.
Biomacromolecules. 2019 Sep 9;20(9):3399-3407. doi: 10.1021/acs.biomac.9b00666. Epub 2019 Aug 8.
Because of the difference in osmotic pressure, most tough hydrogels swell under physiological conditions, which seriously weakens their mechanical properties, limiting their applications in biomedicine. Herein, a novel strategy based on strong and high-density micelle cross-linkings is proposed to prepare nonswellable and tough hydrogel. To realize a strong micelle cross-linker, the synergetic effect of hydrophobic and quadruple hydrogen-bonding interactions is employed by introducing an alkyl chain-protected ureido pyrimidinone moiety into a segmented copolymer backbone. The length of the alkyl is the key factor in determining the strength of the hydrophobic interaction, which was carefully tailored to gain micelles with high strength and suitable solubility. A supramolecular hydrogel was formed in situ by simply linking micelle cross-linkers with poly(ethylene glycol) chains. The strong and high-density micelle cross-linkings restrain multiple effective chains outside the micelle from stretching during swelling, and the deformability of micelle cross-linkings disperses the local stress to maintain the network with high cross-linking density upon loading. Therefore, the hydrogel exhibited an outstanding nonswelling behavior under physiological conditions and excellent mechanical properties with a compressive strength of 4 MPa. The rapid in situ gelation also facilitated injection and cell encapsulation. Meanwhile, it also showed good tissue adhesion, cytocompatibility, and suitable degradability. This novel and facile strategy can offer new insights into the exploitation of cross-linkings to prepare nonswellable hydrogels for biomedical applications.
由于渗透压的差异，大多数坚韧的水凝胶在生理条件下会发生溶胀，这严重削弱了它们的机械性能，限制了它们在生物医学中的应用。在此，提出了一种基于强韧和高密度胶束交联的新策略，以制备不溶胀和坚韧的水凝胶。为了实现强胶束交联剂，通过在嵌段共聚物主链中引入烷基链保护的脲嘧啶酮部分，利用疏水性和四重氢键相互作用的协同效应。烷基的长度是决定疏水性相互作用强度的关键因素，通过仔细调整，可以获得具有高强度和适当溶解度的胶束。通过简单地将胶束交联剂与聚（乙二醇）链连接，即可在原位形成超分子水凝胶。强韧且高密度的胶束交联限制了溶胀过程中多个有效链从胶束外部的拉伸，并通过分散胶束交联的可变形性来维持高交联密度的网络在加载时的状态。因此，该水凝胶在生理条件下表现出优异的不溶胀行为和出色的机械性能，压缩强度达到 4MPa。快速的原位凝胶化还便于注射和细胞封装。同时，它还表现出良好的组织粘附性、细胞相容性和适宜的降解性。这种新颖且简单的策略为开发用于生物医学应用的不溶胀水凝胶提供了新的思路。
