The artificial silk called “polymer amyloid fiber” was not produced by researchers, but by bacteria that were engineered in the laboratory of Fuzhong Zhang, a professor in the Department of Energy, Environment and Chemical Engineering at the McKelvey School of Engineering.
Zhang has worked with spider silk before. In 2018, his laboratory developed bacteria that produced recombinant spider silk, which repeats its natural counterpart in all basic mechanical properties.
In the new work, the research team, which includes first author Jingyao Li, a graduate student in Zhang’s lab, modified the amino acid sequence of spider silk proteins to add new properties to it.
The authors have created various polymeric amyloid proteins using three well-studied amyloid sequences. The resulting proteins had less repetitive amino acid sequences than spider silk, making them easier for artificial bacteria to produce. Ultimately, the bacteria produced a hybrid polymeric amyloid protein with 128 repeat units.
The longer the protein, the stronger and tougher the fiber is. If 128 units are repeated, then its strength is higher than that of steel and Kevlar and all previous recombinant silk fibers. Its strength is even higher than that of some well-known natural spider silk fibers.
The authors of the new work emphasize that they have created an artificial fiber that is better in properties than natural material.