Microbially Produced Artificial Amyloid-Silk Hybrid Protein Fiber is Stronger Than Steel and Kevlar

Spider silk is lighter than a feather but stronger than steel. It's thinner than a human hair but can handle weight hundreds of times its own. Its tensile strength (1.1 gigapascal) beats that of steel (05 gigapascal), and its toughness is comparable to that of Kevlar.

But even nature can't compete with synthetic biology: a new lab-created artificial silk is even stronger. The new material is called polymeric amyloid fiber. It is produced by genetically modified bacteria in the lab of Fuzhong Zhang of Washington University in St. Louis.

From WUSL The Source Newsroom:

To solve this problem, the team redesigned the silk sequence by introducing amyloid sequences that have high tendency to form β-nanocrystals. They created different polymeric amyloid proteins using three well-studied amyloid sequences as representatives. The resulting proteins had less repetitive amino acid sequences than spider silk, making them easier to be produced by engineered bacteria. Ultimately, the bacteria produced a hybrid polymeric amyloid protein with 128 repeating units.


The longer the protein, the stronger and tougher the resulting fiber. The 128-repeat proteins resulted in a fiber with gigapascal strength (a measure of how much force is needed to break a fiber of fixed diameter), which is stronger than common steel. The fibers’ toughness (a measure of how much energy is needed to break a fiber) is higher than Kevlar and all previous recombinant silk fibers. Its strength and toughness are even higher than some reported natural spider silk fibers.

#spider #spidersilk #artificialspidersilk #steel #Kevlar #polymericamyloidfiber #protein #RecombinantProtein #amyloid #materialscience

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