Stretch peptide shows promise for many uses.

A piece of a protein that keeps the aorta elastic even after decades of pumping blood may one day have a variety of biomedical and other applications. This protein contains many copies of a five-amino-acid peptide. That short peptide makes the molecule curl up tight at body temperature and unfold at room temperature, says Dan W. Urry, a molecular biophysicist with the University of Alabama at Birmingham. He and his colleagues discovered that chemical energy and light also have that effect on the peptide.

They produced a transparent film of polymers made from this peptide. By slightly modifying the film's chemical makeup, scientists can alter the bioelastic's properties for a variety of uses, Urry adds.

The film has passed the standard tests for assessing biocompatibility -- how well the body accepts it when implanted. In animals, the film effectively prevented development of adhesive scar tissue, which can bind intestines to the abdominal cavity as they heal after surgery or a wound, says Urry He and his colleagues have also fashioned prototype blood vessels. They think the material, slightly modified, could deliver drugs to the body at a controlled rate or work as biodegradable filler for disposable diapers.

A different film, made from a biopolymer found in the fluid bathing joints, also shows promise for preventing potentially dangerous adhesions after surgery, says Keith Greenawalt of Genzyme Corp. in Cambridge, Mass. That film, made from hyaluronic acid, is now being tested in humans, he says.