It sounds like something straight out of a science fiction book, but scientists have created a “bio-bot,” a walking biological machine powered by heart cells.

Before you start preparing for the upcoming robot apocalypse, bear in mind that these bio-bots are only 7 mm in length. Resembling small springboards, the machines rest on a thick supporting leg while being propelled forward by a thin leg covered with rat cardiac cells. Each time the heart cells beat, the bio-bot takes a step.

These amazing machines were created by a group of graduate students and professors here at the University of Illinois. Vincent Chan, first author of the project’s paper and a research scientist at the University of Illinois, worked on the project as an application of his dissertation “3D Printing of Biological Machines for Biology and Medicine.”

“Originally we were focused on engineering cardiac tissue using a 3D printer to print rat heart cells on soft materials — and we did this to some success,” Chan said. “There was a period where ideas were being thrown around and someone said, ‘Wouldn’t it be cool if we could make bio-bots that did this … ?’ And the rest was history.”

The bio-bots are created by a 3D printer with hydrogel and rat cardiac cells as materials. Hydrogel was chosen as a material because as a soft polymer, it allows for easy testing of different conformations and designs. It also serves as scaffolding for heart muscle cells to allow for even seeding over the propulsion leg of the bio-bot. The whole mechanism is performed in a fluid filled with oxygen and nutrients to power the cells.

This sort of technology is exciting as it presents many new opportunities and possibilities for other biological powered machines. Not only would this expand the variety of materials and methods for researchers to work with, it would also help address issues such as the environmental impact of science and the need for greater use of alternative energy.

“As engineers, we’ve always built things with hard materials — materials that are always 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?” said Rashid Bashir, professor in electrical and computer engineering who worked with Chan on the project.

While the bio-bots project has been completed, research is still being done by the group to expand their capabilities and possible applications.

“As the saying goes, we’re engineers, and we think we can make things better until it breaks,” Chan said. “Well, hopefully it doesn’t break, but you get the point. Right now, the bio-bots walk on their own. But what if we can add control to move, stop, speed up, slow down, steer and even react to the environment? I think there’s a lot of potential, and we’ve got some cool ideas to make that happen.”