Facile synthesis of self-healing gels via frontal polymerization toward acid–base regulatable wound dressing

Advanced pH-regulated wound dressing that can promote wound healing remains a key challenge. To this end, we herein report a self-healing assembly strategy toward pH-regulated gel wound dressing. Firstly, we synthesized acrylic acid (AA)-based Gel 1 by a facile frontal polymerization (FP), which is rich in carboxy groups, endowing the gel with excellent self-healing and pH sensitivity. Then we constructed carboxymethyl chitosan and acrylamide (CMCS-AM)-based Gel 2, which shows reverse pH sensitivity against Gel 1. Thus, the Gel 1/Gel 2 bilayer exhibits different bending behaviors based on the reverse pH sensitivity, providing opportunities for pH regulation. More importantly, the in vivo study indicates that the Gel 1/Gel 2 assembly can effectively adjust the pH microenvironment, which consists of the non-infected wound pH change (from alkalinity to acidity and back again). The Gel 1 can continuously dissociate H⁺ to the wound, while the Gel 2 can adopt these ions, which synergistically realize the pH regulation based on the dissociation–adsorption rates difference and then accelerate the wound healing. This work offers a facile way to construct self-healing gels by FP, as well as a self-healing assembly strategy for advanced wound dressing with pH regulation, which is of great significance in wound healing area. Graphical abstract: [Figure not available: see fulltext.]