These Bots Were Made For Walking: Cells Power Biological Machines

“The idea is that, by being able to design with biological structures, we can harness the power of cells and nature to address challenges facing society,” said Bashir, an Abel Bliss Professor of Engineering. “As engineers, we’ve always built things with hard materials, materials that are very predictable. Yet there are a lot of applications where nature solves a problem in such an elegant way. Can we replicate some of that if we can understand how to put things together with cells?”

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.

“Our goal is to see if we can get this thing to move toward chemical gradients, so we could eventually design something that can look for a specific toxin and then try to neutralize it,” saidBashir, who also is a professor of electrical and computer engineering, and of bioengineering. 

Next, the team will work to enhance control and function, such as integrating neurons to direct motion or cells that respond to light. They are also working on creating robots of different shapes, different numbers of legs, and robots that could climb slopes or steps.

“The idea here is that you can do it by forward-engineering,” said Bashir, who is the director of theMicro and Nanotechnology Laboratory. “We have the design rules to make these millimeter-scale shapes and different physical architectures, which hasn’t been done with this level of control. What we want to do now is add more functionality to it.”

“I think we are just beginning to scratch the surface in this regard,” said graduate student Vincent Chan, first author of the paper. “That is what’s so exciting about this technology – to be able to exploit some of nature’s unique capabilities and utilize it for other beneficial purposes or functions.”

The National Science Foundation supported this work through a Science and Technology Center (Emergent Behavior of Integrated Cellular Systems). Graduate student Mitchell Collens, postdoctoral researcher Kidong Park, chemical and biological engineering professor Hyunjoon Kong, and mechanical science and engineering professor Taher Saif were co-authors of the paper. Bashir also is affiliated with the Frederick Seitz Materials Research Laboratory and the Institute for Genomic Biology at the U. of I.

Contacts and sources:
Liz Ahlberg
University of Illinois at Urbana-Champaign