Pasadena chemist wins national award for new materials research

Chemist David A. Tirrell of Pasadena, Calif., will be honored April 3 by the world's largest scientific society for his innovative approach to making materials for artificial blood vessels and other applications. He will receive the 2001 Award in Polymer Chemistry from the American Chemical Society at its 221st national meeting in San Diego.

The polymer chemist's new compounds are "proteins nature never made," said Tirrell, division chairman of chemistry and chemical engineering at the California Institute of Technology, Pasadena. His research team tries to combine "the strength, toughness and elasticity of synthetic polymers but have them interact with the body in the ways of nature."

"Synthetic polymers and natural ones like DNA and protein are similar in that they're long chains, but they have striking differences in character," Tirrell said. "We can make synthetic polymers in tremendous variety, but with lousy architectural control. In contrast, nature's polymers have precise structure but with very little variety in composition."

Design is the first step in making artificial proteins with which to form replacement blood vessels, for example, according to Tirrell. Surgeons need to be to handle the artificial protein, and it should last as long as needed and be able to interact with surrounding tissue. The reason synthetic polymers currently fail in vessel repair is that cells cannot grow on them.

Next Tirrell's team assembles an artificial gene for insertion into a bacterial cell "factory." When the researchers harvest enough, it's time to mold it into a tube.

"We're trying to understand the mechanism, durability, interaction with endothelial cells [that line blood vessels]," he explained. "Once we have those in place we'll address immune response." Tirrell said he had always been interested in science, but he actually started college intending to be an urban planner - then found he enjoyed his chemistry courses.

He received his undergraduate degree from the Massachusetts Institute of Technology in 1974 and his Ph.D. from the University of Massachusetts in 1978. He is a member of the ACS divisions of polymer chemistry and organic chemistry as well as those of biochemical technology, and polymeric materials: science and engineering.

The ACS Award in Polymer Chemistry is sponsored by ExxonMobil Chemical Co.