Engineers at Washington University in St. Louis have managed to develop a new amyloid silk hybrid protein and produced it in engineered bacteria. The team found out that the fiber made from the material are stronger than natural spider silks.
Spider silks are believed to be one of the strongest and toughest materials on Earth. The artificial silk is dubbed “polymetric amyloid” fiber. It is produced by bacteria that were engineered genetically in Professor Fuzhong Zhang’s lab. He has already worked with spider silk in the past and in 2018 his lab-engineered bacteria produced recombinant spider silk that performs similar to natural silk.
Higher strength than steel
He said that he wondered if the team would be able to create something better than spider silk using their synthetic tech platform. The team faced a major challenge related to recombinant spider silk fiber and had to overcome it without introducing modifications to create the β-nanocrystals, the prime component of natural spider silk that gives it strength.
To overcome the challenge, the team had to make different polymetric amyloid proteins with the aid of three well-studied amyloid sequences. Proteins made from the process show less repetitive amino acid sequences than spider silk making them easier for bacteria to produce.
This process eventually produced a hybrid polymetric amyloid protein with 128 repeating units. The longer the proteins, the tougher will be the fibers produced. Researchers note that the 128-repeat proteins produced a fiber with a gigapascal strength that is higher than common steel.
Tougher than Kevlar
The fiber was also found out to be tougher than Kevlar and all previous recombinant silk fibers. The team says that the research has just begun and their discovery showcases the fact that they can engineer biology to make materials that can give a fight to natural materials in toughness.
Recently, Chinese scientists developed thin strands of ice that can bend and curl. The team of scientists refers to it as “elastic ice microfibers,” and has published the results in the journal Science. Instead of breaking, the ice bends like a wire.
