 Chitin and chitosan are two types of natural polymers found in nature which can be used as biomaterials for wound healing. Recent research has shown that these materials can promote wound healing by stimulating angiogenesis, increasing collagen production, and reducing inflammation. Additionally, nanoscale versions of these materials have been developed and show promise for use in clinical applications. This article was authored by Kazuo Izuma, Ryotaro Izumi, Tomohiro Osaki, and others.