We move thanks to the coordination between many skeletal muscle fibers, all vibrations and stretched synchronized. While some muscles equalize in one direction, others create complicated patterns, helping parts of moving in many ways.
In recent years, scientists and engineers considered muscles as potential cylinders for “biohybrid” robots – machines powered by pliable, artificially cultivated muscle fibers. Such Bio-Bots could blow and move through spaces in which time-honored machines cannot. However, for the most part, scientists were able to produce artificial muscles that pull in one direction, limiting the range of motion of each robot.
Now the MIT engineers have developed Method of artificial muscle tissue It will shine and bend in many coordinated directions. As a demonstration, he lived with an artificial muscle -powered structure, which pulls both concentration and radial, like the iris in the human eye to expand and narrow the student.
Scientists have produced an artificial iris, using a recent “stamping” approach. First of all, they printed a petite, manual stamp pattern with microscopic grooves, each as petite as a single cell. Then they pressed the stamp into a pliable hydrogel and instilled the resulting grooves with real muscle cells. The cells grew along these grooves in the hydrogel, forming fibers. When scientists stimulated the fibers, the muscle shrunk in many directions, after the orientation of the fibers.
“Together with the iris design, we think that we have demonstrated the first skeletal -powered robot, which generates strength in more than one direction. This has been clearly enabled by the Stamp approach, “says Ritu Raman, a professor of career development Eugene Bell for tissue engineering at the MIT MEMIM Department.
The team claims that the stamp can be printed using 3D Tabletop printers and equipped with various microscopic grooves. The stamp can be used to grow complicated muscle patterns – and potentially other types of biological tissues, such as neurons and heart cells – which look and act like their natural counterparts.
“We want to create tissues that repeat the architectural complexity of real tissues,” says Raman. “To do this, you really need such precision in your production.”
She and her colleagues published their open results available on Friday in the journal . Her myth.
Training space
The Ramana laboratory in MIT is aimed at designing biological materials that imitate the detection, activity and reaction of real tissues in the body. In general, its group is aimed at using these bioengineering materials in areas from medicine to machine. For example, he wants to produce artificial tissue that can restore functioning for people with neuromuscular damage. He also studies artificial muscles for pliable robotics, such as muscle -powered swimmers, which move on water with fish flexibility.
Raman previously developed something that can be seen as gymnastic platforms and training procedures for muscle cells raised in the laboratory. She and her colleagues designed a hydrogel “mat”, which encourages muscle cells to grow and join fibers without exfoliation. She also led the way of “exercising” cells through genetic engineering to vibrate in response to lightweight impulses. And her group came up with ways of directing muscle cells to grow in long, parallel lines similar to natural, striped muscles. However, for her group and others the challenge was to design artificial muscle tissue, which moves in many predictable directions.
“One of the cool things in natural muscle tissues is that they do not indicate only in one direction. Take, for example, a round muscular in our iris and around our trachea. And even in our arms and legs, muscle cells do not indicate straight, but at an angle – notes Raman. “Natural muscles have many orientations in the tissue, but we were not able to recreate it in our designed muscles.”
BluePrint muscle
Thinking about ways of growing multidirectional muscle tissue, the team hit a surprisingly simple idea: stamps. The team, partly inspired by the classic Jell-o mold, tried to design a stamp with microscopic patterns that can be printed to the hydrogel, as did the muscle training mats that the group developed earlier. Designs of the printed mat can then serve as a road map from which muscle cells can go and grow.
“The idea is straightforward. But how do you make a stamp with functions as petite as a single cell? And how do you stamp something that is super pliable? This gel is much softer than Jell-O and it is something that is really hard to fill, because it can easily tear, “says Raman.
The team tried differences in the design of stamps and eventually landed on the approach that worked surprisingly well. Scientists have produced a small, manual stamp using very precise printing devices in the myth, which enabled them to print complex groove patterns, each more or less as wide as a single muscle cell, at the bottom of the stamp. Before pressing the stamp to the hydrogel mother, they covered the bottom with protein, which helped the stamps evenly in gel and cut off without sticking or tearing.
As a demonstration, scientists printed a stamp with a pattern similar to microscopic muscles in human iris. Iris contains a muscle ring surrounding the students. This muscle ring consists of an internal circle of muscle fibers arranged concentric, according to a round pattern and an external circle of fibers, which stretch radial, like the rays of the sun. Together, this complex architecture works on the stenosis or extension of the student.
When Raman and her colleagues pressed the iris pattern into a hydrogel mat, they covered the mat with cells, which they designed genetically to react to the light. In one day, the cells fell into microscopic grooves and began to connect into fibers, following the patterns similar to the iris and ultimately grow throughout the muscle, with architecture and size similar to real iris.
When the band stimulated the artificial iris with light impulses, the muscle shrunk in many directions, just like the iris in the human eye. Raman notes that the artificial iris of the syndrome is produced with skeletal muscle cells that take part in the voluntary movement, while muscle tissue in real human iris consists of smooth muscle cells, which are a kind of involuntary muscle tissue. They decided on the model of skeletal muscle cells in a formula similar to the iris to demonstrate the ability to produce complex, multidirectional muscle tissue.
“In this work we wanted to show that we can apply this Stamp approach to create a” robot “that can do things that previous muscle -powered robots cannot do,” says Raman. “We decided to work with skeletal muscle cells. But nothing stops you from doing it with any other type of cell. “
He notes that although the team has used precise printing techniques, stamp design can also be made using conventional 3D printers on the table. Going further, she and her colleagues plan to use the method of stamping to other types of cells, as well as examine various muscle architecture and ways of activating artificial, multidirectional muscles to do a useful work.
“Instead of using inflexible cylinders typical in underwater robots, if we can apply pliable biological robots, we can navigate and be much more energy -saving, and at the same time be completely biodegradable and balanced,” says Raman. “We hope to build it.”
These works were partly supported by the American Naval Research Office, US Army Research Bureau, National Science Foundation and the American National Institutes of Health.