Mechanically strong and on-demand dissoluble chitosan hydrogels for wound dressing applications

Physical hydrogels of pure chitosan preserve the natural properties of chitosan, and therefore are ideal candidates for wound dressing applications, however, their poor mechanical strength severely limits their application. In addition, chitosan dressings tend to adhere to the wounds, making their change difficult. Here physical hydrogels of pure chitosan were prepared by first dissolving chitosan in an alkaline aqueous solution, followed by thermal gelling and solvent change. The gels exhibited better mechanical properties than the gels prepared previously. They were soluble in diluted acetic acid, making them on-demand dissoluble. When used as wound dressing and changed by mechanical debridement, the gels achieved a faster wound closure than gauze. An even faster wound closure was achieved when they were changed by dissolution with acetic acid solution. Besides a faster healing, the on-demand dissoluble dressing could also reduce the formation of scars and reestablish the normal anatomy and function of the skin.