Muscle-inspired lamellar chitosan sponge with photothermal antibacterial and antioxidant properties for hemostasis and accelerated bacteria infected wound healing

Wound dressings with excellent hemostasis, antibacterial, and antioxidant properties are essential for hemorrhagic infected wounds. Herein, inspired by the highly anisotropic and ordered fibrous structure of muscle tissue, we prepared chitosan/polydopamine biomimetic layered sponge dressings loaded with cerium dioxide (CeO2) nanoparticles by a directional freezing method. This composite sponge has an ordered laminate structure, good mechanical properties, excellent moisture absorption, and swelling properties. Thanks to the introduction of PDA, the composite sponge has outstanding photothermal properties and effectively kills bacteria under 808 nm near-infrared (NIR) light. In addition, the CeO2 loaded in the composite sponge also has an excellent ROS scavenging capacity, which protects cells from oxidative stress damage. The rat tail amputation and liver hemostasis experiment proved that this layered sponge had good hemostasis performance. Furthermore, the full-thickness skin defect model infected with S. aureus demonstrated that the composite sponge accelerated wound closure, promoted collagen deposition, down-regulated pro-inflammatory factors (TNF-α), and up-regulated anti-inflammatory factors (IL-10) expression, ultimately promoting wound healing. All the results suggested that this bionic sponge with a directional layered structure has a preferable therapeutic effect on the healing of infected wounds and is expected to be a more advantageous wound dressing.