Multifunctional litchi husk nanocellulose-reinforced bidirectional polymeric hydrogel for sequential therapy of infected wound

The poor mechanical strength and singular therapeutic function of conventional hydrogel dressings have significantly constrained their clinical applicability for treating infected wounds. Consequently, the development of intelligent non-antibiotic dressings that exhibit both high mechanical strength and multiple synergistic therapeutic mechanisms represents a significant challenge. To address this, a “double polymerity-wide crosslinking” strategy was proposed in this work. This strategy successfully constructed a robust bidirectional polymeric hydrogel wound dressing reinforced with litchi husk cellulose nanofibrils. Specifically, the bidirectional polymerization of acrylamide was synergistically regulated by incorporating litchi shell extract and shell-derived cellulose microspheres, while also integrating the natural drug molecule epicatechin. Notably, the AgNPs encapsulated within the litchi shell extract endowed the dressing with remarkable antibacterial properties. Furthermore, the interpenetration of cellulose microspheres within the hydrogel network resulted in a structure exhibiting superior tensile strength, moderate viscosity, and commendable self-healing properties. Concurrently, interactions with the drug molecules facilitated a sequential controlled-release mechanism, enabling initial bacterial eradication followed by inflammation reduction. Molecular docking simulations effectively and sequencing of genes demonstrated stepwise drug delivery and mechanism of action. Moreover, in vivo wound healing experiments conducted on mice with epidermal infections confirmed the material's significant therapeutic efficacy.