High-strength conductive PVA/lignosulfonate/tannic acid/Cu2+ hydrogel for multifunctional wound dressing.

Abstract

Hydrogel wound dressings have evolved from passive moisture barriers into intelligent platforms integrating multiple therapeutic functions. However, reconciling electrical conductivity, mechanical strength, and biocompatibility remains challenging. Herein, we develop a high-strength electroactive hydrogel centered on the biomacromolecule lignosulfonate (LS), which is rich in functional groups for physical crosslinking and bioactivity, serves as the structural backbone of a primary network with poly(vinyl alcohol). Tannic acid (TA) is then anchored into this network via hydrogen bonding, followed by chelation of Cu2+ through TA's ortho-phenolic groups.The resulting hydrogel exhibits an elongation at break of 734%, a swelling ratio of 223%, and a high ionic conductivity of 0.427 S m-1-surpassing most previously reported metal-ion-conductive hydrogels. It also shows 99% DPPH radical scavenging activity. The TA-chelated Cu2+ ensures stable conductivity with negligible Cu2+ release (cumulative 0.605 ppm over 7 days, below the reported cytotoxic threshold), and confers >99% antibacterial rates against E. coli and S. aureus, while maintaining excellent cytocompatibility (>85% cell viability). In a murine full-thickness skin defect model, the conductive hydrogel combined with exogenous electrical stimulation dramatically accelerates wound closure, achieving a healing rate of 96.5% by day 18-markedly higher than the non-stimulated group (90.2%) and the untreated control (74.5%). Histological analysis further confirmed enhanced re-epithelialization and collagen deposition in the stimulated group, indicating improved tissue regeneration. This work establishes a robust, scalable platform for multifunctional conductive hydrogels based on a renewable biomacromolecule, offering a promising strategy for chronic wound management.