Electroassembly of Chitin Nanoparticles to Construct Freestanding Hydrogels and High Porous Aerogels for Wound Healing

The construction of polymeric nanocomponents into a hierarchical structure poses great importance for subsequent biomedical applications. Herein, we report for the first time the electroassembly of chitin nanoparticles (14 nm +/- 3 nm from transmission electron microscopy) to construct thick and freestanding hydrogels, which can be further dried to obtain high porous and tough aerogels for wound healing. The electroassembly is a simple, straightforward, and controllable process, which crucially depends on the pH of the chitin nanoparticle suspension and the degree of deacetylation of chitin. Interestingly, the electroassembly of chitin nanoparticles is completely reversible, suggesting the physical assembly feature of the freestanding hydrogel. By using supercritical CO2 drying and freeze-drying, chitin aerogels and cryogels can be facilely obtained. Because of the intriguing features (i.e., large surface area, interconnected porous structure, and enhanced hydrophilicity), chitin aerogels demonstrate adorable performance to accelerate the healing of wounds.