Chitin is the second most abundant biopolymer in
nature, where it protects crustaceans, parasites, fungi, and other pathogens
from the adverse effects of their environments, hosts, or both.
It is a glucose-based unbranched
widely distributed in nature as the principal component of exoskeletons of
crustaceans and insects as well as of cell walls of some bacteria and fungi.
In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/-) classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior.
Structure of Chitin
Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine, whereas chitosan, a copolymer of N-acetyl-D-glucosamine (approximately 20%) and glucosamine (80%) residues, is a product derived from de-N-acetylation of chitin in the presence of hot alkali. Chitosan is, in fact, a collective name representing a family of de-N-acetylated chitins deacetylated to different degrees. Both chitin / chitosan and their modified derivatives find extensive applications in medicine, agriculture, food, and non-food industries as well. They have emerged as a new class of physiological materials of highly sophisticated functions. All these are the result of their versatile biological activity, excellent biocompatibility, and complete biodegradability in combination with low toxicity. Commercial availability of high-purity forms of chitin, chitosan and the continuous appearance of new types of chitin / chitosan derivatives with more and more useful and specific properties have led to an unlimited R&D efforts on this most versatile amino polysaccharide, chitin to find new applications, which are necessary to realize its full potential.
Chitin metabolism in the Human
Because chitin does not exist in mammals, it had been assumed that the chitinases that degrade it are also restricted to lower life forms. However, chitinases and chitinase-like proteins have recently been noted in mice and human subjects. The prototypic chitinase, acidic mammalian chitinase, was also noted to be induced during T(H)2 inflammation through an IL-13-dependent mechanism. It was also shown to play an important role in the pathogenesis of T(H)2 inflammation and IL-13 effector pathway activation and demonstrated to be expressed in an exaggerated fashion in human asthmatic tissues.
Chitin and Wounds
One of the more important things that chitin, and its products, could be used for is in treating burn patients. Chitin has a remarkable compatibility with living tissue, and has been looked at for its ability to increase the healing of wounds. Chitin itself is the subject of exciting medical experiments. When applied to human wounds and surgical cloths, it accelerates the skin healing process. An acidic mixture of chitin, when applied to burns, also accelerates the healing process. Left on for a few days, it can heal a third-degree bun completely. It has been shown to support the immune system during certain kinds of illness-blocking procedures.
The polysaccharide chitin is found in nature as a major component of the organic fraction of several biocomposites in which an organic matrix is associated with an inorganic fraction. The relationship between the mineral phase and the organic phase implies a high level of molecular recognition. Chitin in mineralized biological systems is present in different polymorphs and has a crucial role in the hierarchical control of the biomineralization processes; the nacre of the mollusk shell is a representative example. Biologically inspired synthesis has been used for the production of mineral-chitin composites. Their actual and future applications move from the medical field as bone repair (chitin-calcium phosphate composites) to the industrial field as catalyst (silica chitin structure replica).
Chitin and Glucosamine Companies
Navamedic announced in January 2006 that it has entered into a long term agreement with the leading Norwegian seafood company Nergård Group and will establish a chitin production facility at Senjahopen. Navamedic will rent facilities adjacent to Nergård Reker, which will supply shrimp shells for the extraction of chitin. This is the starting material for production of glucosamine, an active pharmaceutical ingredient for osteoarthritis symptom treatment.