How does chitosan promote scar-free wound healing?
It has long been known that chitosan-based wound dressings can support scar-free wound healing in animals and humans, even in the case of severe, third-degree burns. However, the mode of action of chitosan in this bioactivity is still unknown. It is clear that chitosan-based dressings can keep a wound clean due to their antimicrobial activities. They can also keep it humid but not too wet as chitosan can act as a superabsorbing material. As the dressing is transparent, the progress of wound healing can be followed without the need to remove the dressing which invariably impacts the formation of a new skin layer. But it would seem that chitosans - or possibly chitosan oligomers slowly produced by the enzymatic degradation of the polymer by human enzymes such as chitotriosidase - also have more subtle influences on the wound healing process, e.g. by specifically inhibiting metalloproteases, thus improving healing in chronic wounds, or by acting as growth factors inducing vascular growth. This is an import area of current research that will greatly profit from the availability of fully defined chitosan oligomers.