Crawling Bio-Robot Runs on Rat Heart Cells

A new biological robot has been made from rat heart cells and synthetic materials, a new study says—and the machine could someday lead to others that will attack diseases inside the human body.

The centimeter-long “biobot" was made by attaching heart muscle cells onto a flexible structure, or body, of hydrogel—the same material used to make contact lenses for human eyes.

To make the biobot’s body, the team used a 3-D printer, which creates solid objects by laying down successive layers of soft materials that fuse together and harden.

Gathering the heart cells was a bit trickier. The researchers removed whole hearts from anesthetized newborn rats, cut the organs into tiny pieces, and then processed the fragments to loosen and separate the heart cells. The cells were then added to the robot body—each bot contains between a few thousand and a few hundred thousand.

"In a few days they start beating, and the bots start to move," explained study co-author Rashid Bashir, an engineer at the University of Illinois at Urbana-Champaign who helped develop the robot.

As the biobot’s “engine,” the heart cells’ contractions bend the machine’s body, causing it to move forward fractions of an inch per second. The biobot has two legs, one that propels it forward and another that acts as a stabilizer.

Heart cells were chosen for the biobot because they spontaneously contract, or “beat,” in time with one another, Bashir said by email.