Molecular design, synthesis strategies and recent advances of hydrogels for wound dressing applications

With the changes in the modern disease spectrum, pressure ulcers, diabetic feet, and vascular-derived diseases caused refractory wounds is increasing rapidly. The development of wound dressings has partly improved the effect of wound management. However, traditional wound dressings can only cover the wound and block bacteria, but are generally powerless to recurrent wound infection and tissue healing. There is an urgent need to develop a new type of wound dressing with comprehensive performance to achieve multiple effects such as protecting the wound site from the external environment, absorbing wound exudate, anti-inflammatory, antibacterial, and accelerating wound healing process. Hydrogel wound dressings have the aforementioned characteristics, and can keep the wound in a moist environment because of the high water content, which is an ideal choice for wound treatment. This review introduces the wound healing process and the development and performance advantages of hydrogel wound dressings. The choice of different preparation materials gives the particularities of different hydrogel wound dressings. It also systematically explains the main physical and chemical crosslinking methods for hydrogel synthesis. Besides, in-depth discussion of four typical hydrogel wound dressings including double network hydrogels, nanocomposite hydrogels, drug-loaded hydrogels and smart hydrogels fully demonstrates the feasibility of developing hydrogels as wound dressing products and their future development trends.