Chitin Research

Like all arthropods (the large group which includes insects, scorpions, shrimp, and lobsters), horseshoe crabs have a hard outer shell, or exoskeleton, that provides protection from predators. Millions of tightly interwoven strands of a cellulose-like material called chitin serve as a tough and flexible glue that holds together the shell. The chitin in horseshoe crabs is favored for research over that found in other arthropods because it is very pure.

Chitin was first investigated in 1811 by Professor Henri Braconnott, who discovered it in the cell walls of mushrooms. In the 1830s, it was isolated in insects and named chitin. Chitosan, a derivative of chitin, was produced in 1859, and since then, research has been conducted to learn about the properties of chitin and chitosan and develop commercial applications for their use.

Chitin is Excitin'

The combination of chitin's remarkable properties makes it extremely versatile. Chitin is natural, non-toxic, non-allergenic, anti-microbial, and biodegradable. It has a strong positive charge, which allows it to bind with negatively charged surfaces or materials, including metals, skin, and macromolecules such as proteins.

Structure of Chitin

Cellulose, chitin, and starch are the three most abundant organic compounds in nature. Cellulose and starch are key carbohydrates that plants use as a food source and to build cell walls.

Chemically, chitin is a polysaccharide. A polysaccharide is a polymer — a large molecule consisting of smaller (and in this case, sugar) molecules strung together. Chitin can be processed into many derivatives, the most readily available being chitosan, which is formed when chitin is heated with a chemical solution. Chitosan has some advantages over chitin because it is more water-soluble.

Chemical Structure of Chitin

By the 1940s, almost 50 patents had been filed for chitin-related products. But commercial development of chitin proceeded slowly, partly because synthetic products were already in use in some applications, and there was a lack of strong federal support for chitin research and the development of chitin products. In the mid-1970s, however, environmental regulations were passed to limit the dumping of untreated shellfish wastes in coastal waters, thus making the processing of chitin from shellfish waste an economical way to comply with the regulations and dispose of the thousands of tons of shellfish waste produced annually. Today, nearly 200 patents have been issued in the United States, in addition to those issued in several other countries worldwide, and there are nearly 15 major processors of chitin and chitosan around the world.

Check Out the Many Uses of Chitin!

	Dr. Paul R. Austin pioneered chitin research at the Unversity of Delaware.

Medical Application: Early on it was found that chitin had wound-healing properties. By the mid-1950s, chitin-coated sutures were being used, which enhanced healing time by 35 to 50%. In the 1970s, researchers with the University of Delaware Sea Grant College Program developed a method to spin pure chitin filaments. These new chitin sutures could be absorbed by the body, eliminating the need for surgical removal. A Japanese firm bought the patent rights, and suture materials are now manufactured in Japan. In addition, this firm uses chitin to make dressings for burns, surface wounds, and skin-graft donor sites, which dramatically accelerate healing and reduce pain compared to standard treatments where the dressings must be removed.

Other medical uses for chitin include anti-bacterial sponges and hospital dressings, artificial blood vessels, contact lenses, tumor inhibition, dental plaque inhibition, and blood cholesterol control. Household products include sponges, diapers, feminine napkins, and tampons.

Water Treatment: Water Purification — As a polymer, chitosan's natural tendency is to form long chains of molecules with positive charges, which act like hooks. These natural hooks catch organic materials, such as oils, detergents, and other contaminants suspended in water. The material then coagulates to form flakes that are easily filtered out. Filtration companies are using chitin in clarifiers to help filter particulates and chemicals from water.

Wastewater Treatment — In Japan, chitosan was first used for wastewater treatment because of its metal-binding properties. It is also good for cleaning up toxic organic compounds, such as PCBs.

Dietary Supplements: Chitosan has properties similar to plant fiber and can significantly bind fat, acting like a sponge in the digestive tract. It is not digestible itself and the bound fat leaves via the body without ever entering the bloodstream.

Cosmetics: Make-up powder; nail polish; moisturizers; face, hand, and body creams; and toothpaste are just a few consumer products that might contain chitin.

Agriculture: Seeds treated with chitosan are larger and stronger and more resistant to fungal diseases. Treating seeds with chitin can increase crop yields by up to 50%.

Chitin is added to commercial feed mixtures containing whey, a by-product of the cheese industry. Many animals find it hard to digest the high-lactose whey. But chitin supports the growth of beneficial microorganisms in the animals' digestive tract — these bacteria produce enzymes that help the animals digest whey.