Researchers develop crawling gel

Scientists at Lehigh University have developed a vibrating gel that can creep like a snake or a snail. The hydrogel rod is made out of polymer acrylamide and water.
According to a report in Scientific American (itself reporting on a published paper in the Proceedings of the National Academy of Sciences), the main difference between the artificial snail and the regular garden variety is that the fake one needs to be stimulated by an external source. The researchers created the driving force by placing the two-centimeter long tubes on a vibrating glass plate covered in silicon rubber. They made small incisions in the rubber; the greater the number of incisions, the faster the artificial snails traveled. The gel could also be made to undulate from side to side like a snake, or inch along like an earthworm.
Since the artificially actuated gels respond to stimuli such as electromagnetic fields, temperature and chemical oscillations, the scientists believe they may be use in applications such as sensors and actuators.