Cellulose-inspired anisotropic hydrogen bond-enhanced strong and tough poly(vinyl alcohol)-chitosan hydrogel for chronic wound healing

• This work fabricates a hydrogen-bond-enhanced anisotropic poly(vinyl alcohol)-chitosan hydrogel (P 5 -CS 1 ), which exhibits a tensile strength of 8.6 MPa and a strain of 713% while maintaining a high water content (77%) and porosity (82%). • While its water content matches that of human tissues, its tensile properties outperform typical PVA-based wound dressings and even surpass those of natural tissues (e.g., muscle and cartilage). • In vitro and in vivo experiments confirm that it possesses excellent bioactivity, which can maintain the L929 cell viability above 100%, reduce the levels of inflammatory factors IL-1 and IL-6, and accelerate the full-thickness wound closure rate in SD rats to 95%. This study proposes a cellulose-biomimetic structural strategy and employs a composite process of directional freezing and salt precipitation to successfully fabricate a hydrogen-bond-enhanced anisotropic Poly(vinyl alcohol) 5 -chitosan hydrogel 1 (P 5 -CS 1 ). This hydrogel exhibits a tensile strength of 8.6 MPa (≈33-fold higher than that of P 5 -CS 1 -FT prepared via the freeze–thaw method) and a toughness of 29.1 ± 1.4 MJ/m 3 (≈80-fold higher than that of the P 5 -CS 1 -FT). This hydrogel simultaneously achieves strain (713%), water content (77%), and porosity (82%). While its water content matches that of human tissues, its tensile properties outperform typical PVA-based wound dressings and even surpass those of natural tissues (e.g., muscle and cartilage). To adapt to diverse chronic wound scenarios, phosphorylated chitosan (PCS) is incorporated to form P 5 -CS 1 -P. In vitro and in vivo experiments confirm that P 5 -CS 1 -P exhibits robust bioactivity, maintaining > 100% L929 viability, reducing IL-1 and IL-6, and accelerating SD rat full-thickness wound closure to 95%. The design integrates physical protection, directional fluid management, and drug delivery, while PCS loading adds anti-inflammatory, antibacterial, and pro-healing functions, offering a promising synergistic strategy for chronic wound care.