Scientists have found a way to coax bacteria into making the toughest form of spider silk. Spider silk is very strong and stretchy, and only now has a way been found to replicate it. Using bacteria and genetic engineering, they have successfully produced dragline silk, which is what spider webs are made of.
Genetically Engineering Spider Silk
Spider silk, or dragline silk, has very impressive and useful properties. It surpasses steel in terms of strength and toughness. A natural material with such attractive qualities could have a number of uses. These include impact-resistant materials and surgical materials. This is why scientists have been trying to produce it for many years. They have tried genetically modified bacteria, yeast as well as goat milk without success.
Dragline silk has a genetic structure composed of long strips of repeating DNA. The organisms used to try to produce it so far have cell mechanisms that chop or alter the dragline silk DNA randomly, making the replication impossible.
Researchers at Washington University in St. Louis have now found a way to go around the challenges found so far. The findings were presented by synthetic biologist Fuzhong Zhang earlier this month at the American Chemical Society’s annual meeting in Orlando, Florida. The new method involves separating DNA repeating sections and placing the pieces into separate E. coli bacteria. Having smaller parts of genetic material reduced the likelihood that the bacteria cells were going to further alter of chop these up. These smaller units of DNA material could then be used to create the code for shorter strands of dragline silk. The silk strands were pieced together using a chemical tag to attach the fibers to each other.
The result of this research is a material that is very similar to dragline silk. The engineered material has comparable toughness, resistance to tearing, and tensile strength as the natural material.