1. Passive dressing (traditional dressing), passively covering the wound and absorbing exudate, providing limited protection for the wound.
2. Interactive dressings, there are many forms of interaction between dressing and the wound surface, such as absorption of exudate and toxic substances, allowing gas exchange, thus creating an ideal environment for healing; barrier outer structure, prevent Invasion of microorganisms in the environment, prevent cross-infection of wounds.
3. Biological active dressing (closed dressing)
The dressing is a combination dressing made of high-molecular materials and biological materials by high-tech method, which is a hot spot in the research and development of wound dressings. The biosynthetic dressing has a double-layer structure, and the outer layer is coated with a polymer material to provide a barrier function corresponding to the epidermis; the main materials selected for the inner layer are collagen, chitosan protective dressing and calcium alginate, which are biocompatible, good water absorption, gas permeability, adhesion, antibacterial and hemostatic effects. It can not only absorb the exudate of the wound, ensure sufficient drainage, but also retain part of exudate in the dressing, maintain a local moist environment that imitates the physiological healing of the wound, facilitate the regeneration of wound granulation tissue and epithelial cells, and accelerate wound healing. In the synthetic dressing, some substances suitable for wound healing, such as drugs, cytokines, growth factors, etc., may be added to form various dressings such as drug dressings, cytokine dressings, growth factor dressings, and the like.