Miniature “bio-bots” developed at the University of Illinois are made of hydrogel and heart cells, but can walk on their own. The key to the bio-bots’ locomotion is asymmetry. Resembling a tiny springboard, each bot has one long, thin leg resting on a stout supporting leg. The thin leg is covered with rat cardiac cells. When the heart cells beat, the long leg pulses, propelling the bio-bot forward. The team uses a 3-D printing method common in rapid prototyping to make the main body of the bot from hydrogel, a soft gelatin-like polymer. This approach allowed the researchers to explore various conformations and adjust their design for maximum speed. The ease of quickly altering design also will allow them to build and test other configurations with an eye toward potential applications. For example, the researchers envision the bio-bots being used for drug screening or chemical analysis, since the bots’ motion can indicate how the cells are responding to the environment.
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