Soft and squishy chemical robots will one day squeeze through tight spots then expand to 10 times larger, offering an advantage over rigid robots. Once a mission is complete, a chembot would biodegrade.

The chembots could get into a building through a crack, for example. They could explore a cave or crevice and dismantle an explosive. Or they might climb ropes, wires or trees. Another tiny idea: One chembot could pack a smaller chembot into a situation, then release it for even more minute explorations.

Researchers at Tufts University have received a $3.3 million contract from the U.S. Defense Advanced Research Projects Agency (DARPA) to build the soft automatons.

ChemBots represent "the convergence of soft materials chemistry and robotics. It is an entirely new way of looking at robots and could someday yield great technological advantage for our armed forces," said Mitchell Zakin, who oversees the program for DARPA.

Tufts neurobiologist Barry Trimmer studies the nervous systems of caterpillars, which grow 10,000-fold in mass after hatching from the larval stage. He studies how they move so flexibly without joints and control movement so precisely with a simple brain.

Using biomaterials and bioengineered polymers, genetic engineering and nanotechnology, Trimmer and colleagues in other fields hope to duplicate some of the caterpillars' traits and behaviors. His lab has already built some prototypes.

"Use of all-biodegradable biopolymer systems will allow use of the robots in a broad range of environmental applications, as well as medical scenarios, without requiring retrieval after completion of the designated tasks," said co-principal investigator David Kaplan biomedical engineer at Tufts. "We expect that these devices will literally be able to disappear after completing their mission."

The chembot would have hair-like sensors for temperature, pressure, chemical and audio/video and to use wireless communication.

Trimmer's long-running caterpillar investigations have been sponsored by the National Science Foundation, the Air Force and other organizations.