Now, 'muscle-powered' bio-bots that can walk 'on their own'

Researchers have successfully developed tiny muscle-powered "bio-bots" that can be controlled with an electric current and can "walk on their own."

The scientists from University of Illinois demonstrated a class of walking "bio-bots" powered by muscle cells and controlled with electrical pulses, giving researchers unprecedented command over their function.

Lead researcher Rashid Bashir, Abel Bliss Professor and head of bioengineering at the U. of I said that the biological actuation driven by cells is a fundamental need for any kind of biological machine one wants to build and they are trying to integrate these 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.

Bashir added that biology is tremendously powerful, and if they can somehow learn to harness its advantages for useful applications, it could bring about a lot of great things.

The bio-bots was powered by beating heart cells from rats. However, heart cells constantly contract, denying researchers control over the bot's motion, which makes it difficult to use heart cells to engineer a bio-bot that can be turned on and off, sped up or slowed down.

The new bio-bots are powered by a strip of skeletal muscle cells that can be triggered by an electric pulse. This gives the researchers a simple way to control the bio-bots and opens the possibilities for other forward design principles, so engineers can customize bio-bots for specific applications.

The design is inspired by the muscle-tendon-bone complex found in nature. There is a backbone of 3-D 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 study was published online in the Proceedings of the National Academy of Science.