Chitin
Chitin is widely existed in shell of crab, shrimp and insect's shell, fungi cell and water plant's cell wall. Chitin is mainly made from shell of shrimp and crab, which is abundant basic raw material for chitosan and glucosamine through the techniques of decalcification, deproteinization and decoloration etc.Chitin's properties as a flexible and strong material make it favorable as surgical thread. Its biodegradibility means it wears away with time as the wound heals. Moreover, chitin has some unusual properties that accelerate healing of wounds in humans.
Occupations associated with high environmental chitin levels, such as shellfish processors, are prone to high incidences of asthma. Recent studies have suggested that chitin may play a role in a possible pathway in human allergic disease. Specifically, mice treated with chitin develop an allergic response, characterized by a build-up of interleukin-4 expressing innate immune cells. In these treated mice, additional treatment with a chitinase enzyme abolishes the response.