These bots were made for walking
16 November 2012
They’re soft, biocompatible, about 7mm long and are able to walk by themselves. Miniature 'bio-bots' developed at the University of Illinois are making tracks in synthetic biology.
Miniature 'bio-bots' developed at the University of Illinois are made of hydrogel and heart cells, but can walk on their own (photo: Elise A. Corbin)
The walking bio-bots are functional machines using only hydrogel, heart cells and a 3D printer. With an altered design, they could be customised for specific applications in medicine, energy or the environment. Research team leader, Professor Rashid Bashir of the University of Illinois at Urbana-Champaign, explains:
“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. 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 3D 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, Bashir envisages 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. By integrating cells that respond to certain stimuli, such as chemical gradients, the bio-bots could be used as sensors.
“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. Now you can think about a sensor that’s moving and constantly sampling and doing something useful, in medicine and the environment. The applications could be many, depending on what cell types we use and where we want to go with it.”
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.
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