Modular, Muscle-Powered Walking Bio-Bots Respond to Light
A new class of miniature biological robots, or bio-bots, are powered by muscle cells that have been genetically engineered to respond to light - giving researchers control over the bots' motion, a key step toward their use in applications for health, sensing, and the environment. Led by Rashid Bashir, the University of Illinois head of bioengineering, the group previously demonstrated bio-bots that were activated with an electrical field, but electricity can cause adverse side effects to a biological environment and does not allow for selective stimulation of distinct regions of muscle to steer the bio-bot. The new light-stimulation technique is less invasive and allows the researchers to steer the bio-bots in different directions. The bio-bots turn and walk toward the light stimulus.
Transcript
00:00:00 My research is focused on developing high-resolution 3D bio-printing technologies for applications in biomedical engineering. We use these 3D printers to design and build soft robotic devices powered by living skeletal muscle. These types of bio-integrated robots, or bio-bots, combine the advantages of building with synthetic materials and biological materials, allowing us to design machines that target a variety of applications in health, security, and the environment. Our latest study demonstrates that the muscle used to power our bio-bots can be genetically engineered to enable control via a light stimulus. This type of light-control, called optogenetics, gives us an easy way to forward engineer muscle-powered bio-bots with more complex functional behaviors. The skeletal muscle rings we engineer are shaped like rings or rubber bands because
00:00:34 we want them to be modular - this means we can treat them as building blocks that can be combined with any 3D printed skeleton to make bio-bots for a variety of different applications. Here, we see me picking up the muscle rubber band with sterile tweezers and transferring it to one of our one-leg walking bio-bots. We all know that exercise makes muscle stronger. Because our bio-bots are made with optogenetic, or light-controlled, muscle, we can exercise them using light. Comparing the control group bio-bots that haven’t been exercised with the exercise group bio-bots that have been exercised shows us that exercised bio-bots produce more force, as expected. This is the first demonstration of light-induced improvement in muscle functional performance. When optogenetic muscle is triggered by a blue light stimulus, it generates a contractile
00:01:20 force. When this muscle is coupled to a 3D printed skeleton, this contractile force can be converted into useful work. Here, we use blue light to control a one-leg bio-bot that walks across a substrate. We have previously published work on bio-bots controlled by an electrical stimulus. But an optical stimulus is desirable for many reasons. Its less invasive, and it can be used to selectively stimulate only regions of muscle that you want to activate. For example, when you stimulate a completely symmetric two-leg bio-bot electrically, the two muscle rings contract equally and you observe no net locomotion. However, when you stimulate a two-leg bio-bot optically, you have the option to stimulate one muscle ring or parts of a muscle ring. In this way, you can make the bio-bot walk in one direction or another,
00:02:08 or rotate in any direction you choose.