NEW YORK (TIP): Imagine walking robots powered by muscle cells and controlled with electrical pulses that can give them an unprecedented command over their function. Engineers at University of Illinois at Urbana-Champaign have demonstrated a class of “bio-bots” that are powered by a strip of skeletal muscle cells that can be triggered by an electric pulse.

“We are trying to integrate the principles of engineering with biology in a way that can be used to design and develop biological machines and systems for environmental and medical applications,” explained Rashid Bashir, head of bioengineering at University of Illinois.

Skeletal muscles cells are very attractive because you can pace them using external signals, Bashir added. The design is inspired by the muscle-tendon-bone complex found in nature. There is a backbone of 3D printed hydrogel, strong enough to give the bio-bot structure but flexible enough to bend like a joint. Two posts serve to anchor a strip of muscle to the backbone, like tendons attach muscle to bone, but the posts also act as feet for the bio-bot.

A bot’s speed can be controlled by adjusting the frequency of the electric pulses. A higher frequency causes the muscle to contract faster, thus speeding up the bio-bot’s progress. “The ‘bio-bots’ could eventually evolve into a generation of biological machines that could aid in drug delivery, surgical robotics, ‘smart’ implants, or mobile environmental analyzers, among countless other applications,” said Caroline Cvetkovic, a graduate student and co-first author of the paper. The group published its work in the online edition of Proceedings of the National Academy of Science.