Dual-Network Nanocellulose Hydrogels with Dynamic Schiff Base and Borate Bonds for Rapid Self-Healing and Antioxidant...

Hydrogels from renewable polymers are attractive as wound dressings; however, integrating mechanical robustness, rapid autonomous self-healing, and bioactivity in a single polysaccharide-based system remains challenging. Here, we report a sustainable dual-network (DN) nanocellulose hydrogel constructed via dynamic Schiff base and borate chemistry. Dialdehyde cellulose nanofibers (DACNF), prepared by periodate oxidation, were reversibly cross-linked with carboxymethyl chitosan (CMCS) to form a dynamic imine network, while a secondary energy-dissipative network was introduced through borate ester interactions between poly vinyl alcohol (PVA) and borax. Tannic acid (TA) was incorporated to provide antioxidant and antibacterial functions. The resulting DN hydrogel exhibited rapid self-healing (macroscopic integrity restored within 30 s upon contact), high stretchability (elongation at break up to ∼1515%), and strong wet-tissue adhesion. In addition, it showed efficient radical-scavenging activity (66 ± 2% DPPH scavenging) and antibacterial efficacy (>99%) against Staphylococcus aureus and Escherichia coli. Cytocompatibility with human foreskin fibroblasts and accelerated healing in a rat full-thickness burn model further supported its suitability as a multifunctional dressing. This work highlights how dynamic covalent/coordination networks enable performance integration in biobased hydrogels for wound-care applications.