Titin is the largest known protein in nature; it consists of 244 individually folded protein regions connected by an unstructured sequence of peptides. Also titin is one of the three main protein components of muscle tissue.
The production of artificial muscle fibers has long been of interest to researchers. Therefore, they tried to develop materials with similar muscle properties. They can be used, for example, in soft robotics.
The authors of the new work wondered why they should not produce the necessary muscles directly, only to use for this not animals, but microbes.
There are problems that prevent bacteria from making large proteins. Therefore, the research team engineered the bacteria to assemble smaller protein segments into ultra-high molecular weight polymers, about two megadaltons in size – about 50 times the average bacterial protein.
They then used a wet-spinning approach to turn proteins into fibers about ten microns in diameter, about one tenth the thickness of a human hair.
As a result of the work, the authors analyzed the structure of these fibers in order to understand what molecular mechanisms give it such strength, as well as the ability to dissipate mechanical energy in the form of heat. The fibers are stronger than Kevlar.
Titin production will be inexpensive and scalable. We can use artificial muscle fibers instead of real animal tissues, for example.
Fujong Zhang, professor of the Department of Energy, Environment and Chemical Engineering.
The authors believe that the results of their work can be used for biomedicine, since the obtained protein is almost identical to our muscle tissue. It is also biocompatible so it can be an excellent suture material.