Nanocellulose hydrogels with tunable porosity, high elongation, and autonomous healing for promote wound repair

Conventional hydrogel dressings often fail to simultaneously achieve adhesivity, rapid self-healing, and structural adaptability required for dynamic and irregular wound environments. Here, we report the fabrication of a dual-crosslinked nanocellulose hydrogel via a gradient temperature-controlled strategy, which confers tissue adhesion, tunable porosity, and rapid self-repair. In this process, cellulose nanofibers (CNF) and polyvinyl alcohol (PVA) were dissolved at 90 °C, gelatin was introduced at 70 °C, and reversible borate ester crosslinking was induced at 37 °C, enabling controlled assembly and uniform network formation. The resulting hydrogel exhibited exceptional mechanical performance, with stretchability exceeding 1000% strain and ultrafast self-healing within 8 s at 37 °C. It also showed intrinsic antibacterial activity, achieving an 84.3% inhibition rate against Staphylococcus aureus. Mechanistic studies revealed that the stepwise assembly stabilized CNF/PVA hydrogen-bonded frameworks and facilitated energy dissipation via dynamic borate bond reconfiguration, thereby underpinning the multifunctional properties. In vivo, the hydrogel accelerated wound closure (95.8% at day 14 vs. 84.4% for gauze) and enhanced collagen deposition. Furthermore, it conformed seamlessly to irregular anatomical sites such as joints, minimized secondary tissue damage, and maintained reliable adhesion strength (4.38 kPa). This design thus establishes a rational paradigm for developing next-generation, multifunctional hydrogel dressings for precision wound care.