Synthetic biology allows microbes to build stronger muscle fibers than Kevlar

No animal was harmed in the production of synthetic muscle fibers, which are stronger than Kevlar.

Would you wear muscle fiber clothing? Use them to tie your shoes or even wear them as a belt? It might sound a little strange, but if these fibers can withstand more energy before they break than cotton, silk, nylon, or even Kevlar, then why not?

Don’t worry, this muscle could be produced without harming a single animal.

Researchers at the McKelvey School of Engineering at Washington University in St. Louis have developed a synthetic chemistry approach to polymerize proteins inside modified microbes. This allowed the microbes to produce the high molecular weight muscle protein titin, which was then spun into fibers.

Their research was published on Monday, August 30, 2021 in the journal Natural communications.

Also: “Its production can be cheap and scalable. It can enable many applications that people had thought of before, but with natural muscle fibers, ”said Fuzhong Zhang, professor in the Department of Energy, Environmental and Chemical Engineering. Now, these applications can come to fruition without the need for actual animal tissue.

The synthetic muscle protein produced in Zhang’s lab is titin, one of the three major protein components of muscle tissue. The large molecular size of titin is essential for its mechanical properties. “It is the largest protein known in nature,” said Cameron Sargent, doctoral student in the Division of Biological and Biomedical Sciences and first author of the article alongside Christopher Bowen, recent PhD in the Department of Energy, environment and chemistry. Engineering.

Muscle fibers have been of interest for a long time, said Zhang. Researchers have tried to design materials with properties similar to those of muscles for various applications, such as soft robotics. “We asked ourselves, ‘Why don’t we make synthetic muscles directly? ” “, did he declare. “But we’re not going to harvest them from animals, we’ll be using microbes to do it.”

To get around some of the problems that typically prevent bacteria from making large proteins, the research team designed bacteria to reconstitute smaller segments of the protein into ultra-high molecular weight polymers of about two megadaltons, or roughly. 50 times the size of an average bacteria. protein. They then used a wet spinning process to convert the protein into fibers about ten microns in diameter, or one tenth of the thickness of a human hair.

Work with collaborators Young Shin Jun, professor in the Department of Energy, Environmental and Chemical Engineering, and Sinan Keten, professor in the Department of Mechanical Engineering of Northwestern University, the group then analyzed the structure of these fibers to identify the molecular mechanisms that enable their unique combination of exceptional toughness, strength and damping capacity, or the ability to dissipate mechanical energy in the form of heat.

Aside from fancy clothing or protective armor (again, the fibers are stronger than Kevlar, the material used in bulletproof vests), Sargent pointed out that this material also has many potential biomedical applications. . Because it is almost identical to the proteins found in muscle tissue, this synthetic material is presumably biocompatible and therefore could be an excellent material for sutures, tissue engineering, etc.

Zhang’s research team does not intend to stop at synthetic muscle fibers. The future will likely contain more unique materials activated by their microbial synthesis strategy. Bowen, Cameron, and Zhang filed for a research-based patent.

“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 and then put them in this platform for polymerization and create bigger and longer proteins for various material applications with greater durability.”

Reference: August 30, 2021, Nature Communication.
DOI: 10.1038 / s41467-021-25360-6