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 PEG₄₀₀₀ 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 (<i>G</i>′) and loss modulus (<i>G</i>″) of the hydrogel increased obviously as the concentration of dialdehyde-functionalized PEG₄₀₀₀ (DF-PEG₄₀₀₀) 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