Enzyme-Regulated Fast Self-Healing of a Pillararene-Based Hydrogel

Self-healing, one of the exciting properties of materials, is frequently used to repair the damage of biological and artificial systems. Here we have used enzymatic catalysis approaches to develop a fast self-healing hydrogel, which has been constructed by dynamic aldimine cross-linking of pillar[5]arene-derivant and dialdehyde-functionalized PEG followed by encapsulation of glucose oxidase (GOx) and catalase (CAT). In specific, the two hydroxyl groups at terminal of PEG 4000 are functionalized with benzaldehydes that can interact with amino-containing pillar[5]arene-derivant through dynamic aldimine cross-links, resulting in reversible dynamic hydrogels. Modulus analysis indicated that storage modulus ( G ′) and loss modulus ( G ″) of the hydrogel increased obviously as the concentration of dialdehyde-functionalized PEG 4000 (DF-PEG 4000 ) increased or the pH values decreased. Once glucose oxidase (GOx) and catalase (CAT) are located, the hydrogel could be fast repaired, with self-healing efficiency up to 100%. Notably tensile test showed that the repair process of pillararene-based hydrogel can finish in several minutes upon enzyme catalysis, while it needed more than 24 h to achieve this recovery without enzymes. This enzyme-regulated self-healing hydrogel would hold promise for delivering drugs and for soft tissue regeneration in the future.

自愈是材料令人兴奋的特性之一，经常用于修复生物和人工系统的损伤。在这里，我们使用酶催化方法开发了一种快速自修复水凝胶，该水凝胶是通过柱[5]芳烃衍生物和二醛功能化 PEG 的动态醛亚胺交联，然后封装葡萄糖氧化酶 (GOx) 和过氧化氢酶 (CAT) 构建的。具体来说，PEG 4000 末端的两个羟基被苯甲醛官能化，苯甲醛可以通过动态醛亚胺交联与含氨基的柱[5]芳烃衍生物相互作用，从而产生可逆的动态水凝胶。模量分析表明，随着二醛功能化PEG 4000（DF-PEG 4000）浓度的增加或pH值的降低，水凝胶的储能模量（G'）和损耗模量（G''）明显增加。一旦找到葡萄糖氧化酶（GOx）和过氧化氢酶（CAT），水凝胶就可以快速修复，自愈效率高达100%。值得注意的是，拉伸测试表明，柱芳烃基水凝胶的修复过程在酶催化下可以在几分钟内完成，而在没有酶催化的情况下需要超过24小时才能实现这种恢复。这种酶调节的自愈水凝胶有望在未来用于输送药物和软组织再生。