April 29 (UPI) -- Scientists at the University of Illinois at Urbana-Champaign have created a biohybrid robot featuring an actual rat spinal cord and a tissue-engineered muscle system.
After culturing the system in the lab for a week, the spinal cord began to generate electrical signals that caused the artificial muscles to contract.
When scientists compared the development of the tissue-engineered spinobot with in vivo spinal cord development, they observed several similarities.
To test the spinobot's performance, scientist added the neurotransmitter glutamate to the solution in which the organic biobot was resting. The addition of higher and higher concentrations of glutamate caused the spinal cord neurons to fire more rapidly, triggering repeated, rhythmic contractions of the synthetic muscle.
"These neurotransmitters are the cues for the muscle to contract. Here we chose to use only the most common excitatory neurotransmitter, glutamate," Collin Kaufman, neuroscience graduate student at the University of Illinois, told UPI in an email. "However, we believe that by creating a neurotransmitter cocktail with a mixture of neurotransmitters in spinal neurons, glutamate and serotonin, we would be able to change the pattern of firing."
The breakthrough biobot, described Tuesday in the journal APL Bioengineering, could be used to study diseases of the nervous system, such as Lou Gehrig's disease, also known as amyotrophic lateral sclerosis, or ALS.
"Most studies of ALS are either behavioral or study specific time-points when the animal was prepared for histology because it is very difficult to study the peripheral nervous system -- neurons that extend from the spinal cord out to all your muscles," Kaufman said.
Using the new biobot, or hybrid spinal cord-synthetic muscle systems like it, scientists could closely study nervous system diseases and their effects on tissue in real time.
"The modular component of our platform means that we can replace our 'healthy' tissue with mutant tissue derived from models of any neuro-muscular disease or disorder -- including myasthenia gravis, ALS and muscular dystrophy -- and study how the diseased tissue alters development and function at the junction between neurons and muscle," Kaufman said.
In the future, hybrid biobots could also be used as surgical training models, allowing medical students to practice surgeries on real biological tissue.
Eventually, hybrid biobots could become programmable robotic systems. But while promising, the new biobot is only one very early step in the quest to build sophisticated, life-like robots.
"This technology is probably not yet ready to scale into what we think of as a walking, talking robot," Kaufman said. "As tissues get larger, they rely on vascularization (blood vessels) to provide the deepest parts of the tissue with nutrients and to carry away metabolic waste. Several labs are working on vascularizing engineered tissues. This will be a very important step toward being able to grow larger, more complex biological robots."
For now, Kaufman and his colleagues are working to create more complex spinal cord-muscle systems, featuring the coordinated control of multiple muscles.