The silk produced by spiders is one of the strongest and most flexible materials known. Its hardness exceeds that of artificial fibers such as Nylon or Kevlar, and it is capable of stretching up to 40% without deforming, returning to its original shape afterwards .
However, they have emerged a tough competitor: fibers that have been produced thanks to bacteria that were genetically modified in the laboratory of Fuzhong Zhang , of the Department of Energy, Environmental Engineering and Chemistry at the McKelvey School of Engineering of the University of Washington in Saint Louis.
Stronger and more resistant fibers
The research team modified the amino acid sequence of spider silk proteins to introduce new properties, while retaining some of the attractive characteristics of spider silk .
In this way, fibers stronger and more resistant than some natural spider silks have been obtained by means of hybrid proteins of designer amyloid silk produced in genetically modified bacteria.
The 128-repeat proteins resulted in a fiber with a gigapascal force (a measure of how much force it takes to break a fixed diameter fiber), which is stronger than ordinary steel. Fiber toughness (a measure of how much energy it takes to break a fiber) is higher than Kevlar and all previous recombinant silk fibers. Its strength and toughness are even higher than that of some reported natural spider silk fibers .