Today, clothing is made from many sustainable materials, such as bamboo, recycled plastics, pine or hemp. Researchers are still looking for materials that would provide even better properties. Can you imagine clothes made of muscle fibers? It is not a horror idea, but a reality. Muscle fibers have exceptional properties, and scientists have been able to produce synthetic muscle fibers that are stronger than kevlar. As these fibers are synthetic, no animals need to be used for them.

Muscle fiber clothing

Synthetic muscle fibers have been produced by scientists at the University of Washington at St. Louis. A team of scientists used microbes to polymerize proteins which were then spun into fibers. It’s similar to when worms produce silk, but in this case microbes produce muscle fibers. The microbes can be modified in such a way that the fibers have the required properties and the fibers can, for example, be very resistant to damage.

“Its production can be cheap and scalable. It may enable many applications that people had previously thought about, but with natural muscle fibers,” said Fuzhong Zhang, professor in the Department of Energy, Environmental & Chemical Engineering, and one of the study authors.

Muscle fibers made from “titin” protein

A protein called “titin” is used to make synthetic muscle fibers. An adult has about half a kilogram of this protein in his body.

Titin was desirable because of its molecular size. “It’s the largest known protein in nature,” said Cameron Sargent, a Ph.D. student in the Division of Biological and Biomedical Sciences and a first author on the paper.

Scientists have long considered the use of muscle fibers, but it would be unethical to use animals to obtain them. “We wondered,‘ Why don’t we just directly make synthetic muscles?’” Zhang said. “But we’re not going to harvest them from animals, we’ll use microbes to do it.”

It would be difficult to make bacteria that make big proteins. Instead, bacteria have formed that produce smaller proteins that fold into very strong structures. The protein formed has about 50 times the molecular weight of the average bacterial protein. A wet spinning process is used to form the fiber. Finished muscle fibers are 10 times thinner than human hair. Since it is possible to modify the properties of the fibers, it will be possible to make clothes from them which, for example, are softer or dry faster.

“The beauty of the system is that it really is a platform that can be applied anywhere,” Sargent said. “We can take proteins from different natural contexts, then put them into this platform for polymerization and create larger, longer proteins for various material applications with a greater sustainability.”

It is used not only for clothing, but also for medicine

As the fibers are very similar to real muscle, they can be used in various medical procedures. This can be, for example, sewing wounds. The advantage of this material is that it is biodegradable and does not cause pollution.

“By harnessing the biosynthetic power of microbes, this work has produced a novel high-performance material that recaptures not only the most desirable mechanical properties of natural muscle fibers (ie, high damping capacity and rapid mechanical recovery) but also high strength and toughness, higher even than that of many manmade and natural high-performance fiber,” the researchers conclude.


Image credit: Washington University in St. Louis.