Engineers at the University of Illinois at Urbana-Champaign have developed tiny biological machines capable of walking by using twitching muscle cells. Remarkably, these self-propelled "bio-bots" can be controlled externally using electrical pulses. Oh, and they're 3D printed.
We typically imagine robots as being comprised of metal gears and electronic parts. But by combining biological components, such as cells and tissues, with soft robotics, researchers are creating biological machines capable of sensing, processing, and producing force.
"We're 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," noted UoI professor Rashid Bashir in a statement. "Biology is tremendously powerful, and if we can somehow learn to harness its advantages for useful applications, it could bring about a lot of great things."
And by great things Bashir imagines fleets of tiny biological machines entering into the human body to neutralize toxins, assist in drug delivery, perform internal surgery, or to serve as 'smart implants.' They could also work as mobile analyzers that monitor the environment and perform clean-up duties.
Inspired by Nature
A few years ago, Bashir's team successfully demonstrated walking bio-bots that could move by using beating heart cells taken from rats. But the heart cells were constantly contracting, making it impossible to control the bots' motion.
But the new design is more intuitive — one that's inspired by the muscle-tendon-bone complex found in biological organisms. A bio-bot's structural backbone is provided by a 3D printed hydrogel. It's strong but flexible, so it can bend like a joint. And like tendons that attach muscle to bone, two posts anchor a tiny strip of muscle to the structure. The posts also act as feet for the bio-bot.
Speed is controlled by adjusting the frequency of the electric pulses. Higher frequencies cause the muscle to contract faster, thus speeding up the bio-bot's locomotion.
"It's only natural that we would start from a bio-mimetic design principle, such as the native organization of the musculoskeletal system, as a jumping-off point," noted co-author Caroline Cvetkovic. "This work represents an important first step in the development and control of biological machines that can be stimulated, trained, or programmed to do work."
The researchers have some wild plans for the future — like adding neurons so that the bio-bots can be steered in different directions with light or chemicals.
Read the entire study at PNAS: "Three-dimensionally printed biological machines powered by skeletal muscle". Additional information via University of Illinois.
Image: Janet Sinn-Hanlon
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