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Shrimp is highly prized among those who love seafood cuisine. But it may no longer be just the meat that's in demand. Scientists are buying up the shells, too.

The shrimp shells, like those of crab and other crustaceans, contain a natural polymer called chitosan, which is used in a wide variety of biomedical, industrial, cosmetic, and even dietary applications.

The shells are taken from the shrimp and boiled in lye. What's left is chitin, which is further purified before the acetyl (CH3CO) group is taken off and turned into the polysaccharide called chitosan. Further purification is necessary before the chitosan reaches its signature form: a beige-white powder.

Chitosan is both biodegradable and biocompatible. Its chemical form is almost identical to cellulose, which is made up of sugars that the body metabolizes in order to live. That's why the biomedical world is so interested in its potential application.

It's Mother Nature's ideal bandage, according to Kenton Gregory, HemCon co-founder. HemCon produces a wound dressing with chitosan that stops severe bleeding on contact. It not only binds red blood cells, but chitosan has an added feature. It binds endotoxins and bacteria so tightly that they are inactivated.

Chitosan has been used for many years in water treatment, where it "flocks" or clumps together oils, bacteria, and other pathogens in water. It is also currently used in pool cleaners, cosmetics, and as a diet pill.

See also "Chitosan: A polymer from the sea," Northwest Science & Technology, Autumn 2001, pp. 16-19.