 Chitin and chytosan are two types of natural polymers found in the exoskeletons of crustaceans and insects. They are both composed of long strands of enocidal glucosamine molecules linked together by glycosidic bonds. These polymers have been shown to promote wound healing when applied topically due to their ability to stimulate collagen production and reduce inflammation. Recently, research has focused on developing nanoscale versions of these polymers, which can be used as scaffolds for tissue engineering and regenerative medicine. This article was authored by Kazuo Izuma, Ryotaro Izumi, Tomohiro Osaki, and others.