Development of a Dual-Layer Near-infrared-Responsive Hydrogel/Membrane Wound Dressing for Enhanced Healing

Asymmetric wound dressings (AWD) are currently being developed to mimic the structural and functional characteristics of skin layers. To further enhance their performance, near-infrared (NIR) responsiveness has been explored to enable mild-temperature therapy, improve antibacterial properties, and control drug release. In this work, a NIR responsive AWD was developed by exploring a self-healing hydrogel based on oxidized hyaluronic acid (OHA, 2 % w/v), succinyl-chitosan (CS-SA, 2 % w/v) and polydopamine (PDA, 0.01% w/v) nanoparticles with 250 nm, as a bottom layer, and a polycaprolactone (16 % w/v)/lignin (0, 2, or 3 % w/v) (PCL/LIG) electrospun membrane as top layer. The membrane provided a dense and randomly organized fibrous structure with slow degradation and hydrophobic character (water contact angle of 110 - 120°), ensuring mechanical support and a protective barrier to the wound site. The hydrogel presented a self-healing behavior and PDA nanoparticles conferred photothermal capacity to the wound dressing, achieving a temperature increase of 12.2 ± 0.2 °C after 10 min of NIR irradiation. Moreover, peppermint ( Mentha × piperita ) essential oil was incorporated into the hydrogel, further enhancing the antibacterial properties, and revealing a synergistic antibacterial effect under NIR exposure, with a bacterial viability of 18% for Staphylococcus aureus and 29% for Escherichia coli after 3 irradiations. Moreover, the in vitro data confirmed the cytocompatibility of both layers and the AWD with fibroblasts, even after one and three NIR laser irradiations. Overall, these results highlight the potential of NIR-responsive AWD to accelerate wound healing through combined structural, antibacterial, and photothermal effects.