We previously reported that researchers from the University of Illinois at Urbana-Champaign had engineered a small walking “bio-bot”, powered by autonomous rat cardiac cells. The main challenge then was that cardiac cells contract spontaneously, so the contraption wasn’t controllable. The team has now made an improved version of the bio-bot that is fully controllable.
It’s made by seeding skeletal muscle myoblasts onto a 3D-printed hydrogel scaffolding. The hydrogel backbone is composed of two stiff pillars and a compliant connecting beam. The myoblasts attach and anchor to the two pillars, and when they contract, they pull the pillars towards each other to bend the beam, mimicking the natural bone-tendon-muscle actuation unit. The asymmetry of the backbone allows for movement in the direction of contraction. The skeletal muscle cells themselves respond to electric signals, and so the bio-bot’s speed can be controlled by varying the frequency of the stimulation: higher frequency signals lead to faster contractions and quicker movement. It had a maximum speed of 156 microns per second, which doesn’t sound tremendously speedy, and roughly equates to about 1.5 times its 6 mm body length each minute.
The team sees a variety of applications for their locomotive innovation, made especially possible by the ease of designing and prototyping through 3D-printing.
“It’s exciting to think that this system 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, co-first author of the paper.
“The idea of doing forward engineering with these cell-based structures is very exciting,” said Rashir Bashid, principal investigator of the project. “Our goal is for these devices to be used as autonomous sensors. We want it to sense a specific chemical and move towards it, then release agents to neutralize the toxin, for example. Being in control of the actuation is a big step forward toward that goal.”
Study in Proceedings of the National Academy of Sciences: Three-dimensionally printed biological machines powered by skeletal muscle…
University of Illinois: Muscle-powered bio-bots walk on command…
(hat tip: Engadget)