How to make super-strong spider silk without counting on the aggressiveness and territoriality of spiders? With the silkworms. Silk is stronger than steel… if used correctly. Although spiders play a major role in silk production, new research led by Tianjin University shows that silkworms generate silks 70 percent stronger than spider silks by removing a sticky outer layer and hand-spinning the silk. silk.
“Our finding reverses the previous perception that silkworm silk cannot compete with spider silk in mechanical performance,” said Zhi Lin, a biochemist at Tianjin University and a co-author of the paper published in the journal Matter.
Historically, silkworm silk has been used in fashion as a source for luxury robes and clothing suitable for royalty, but it is currently used more in biomedicine and for tissue regeneration experiments due to its mechanical properties, biocompatibility, and biodegradability. .
Creating Extra Strong Worm Silk
Silkworm silks are not very durable or strong compared to spider-spun silk , but the researchers were inspired by the artificial spinning of spider egg silk, which is a close relative of silkworm silk. silkworm and it has been shown to work well in the spinning process to see if they could overcome the strength of spider webs.
The research group wanted to use commercially available mulberry silkworms ( Bombyx mori) because they are more accessible and easier to handle, but natural silkworm fiber is made from a core encased in a silk glue that interferes with the spinning of silkworms. fibers for commercial purposes. They determined that the best method to dissolve the glue while minimizing the degradation of silk proteins was by boiling it in a special bath of chemicals. And then, to solidify the silk back into continuous fibers, they tested the silk proteins in baths containing different metals and sugars to find the method that produced the best rate of fiber formation.
Tests of the mechanical properties of this silk revealed a tensile strength, the maximum stress a material can withstand while being stretched or pulled before breaking, of 2,000 MPa, which is more than 70% higher than that of silk. spider drag silks. Silk is also extraordinarily stiff, significantly stiffer than any other known natural silk.
“Since silkworm silk is structurally very similar to egg-case spider silk, which has previously been shown to work well in a mixture of zinc and iron baths, we thought to try this alternative method to avoid dangerous conditions.” used elsewhere,” says Lin. “Sucrose, a form of sugar, can increase the density and viscosity of the coagulation bath, thereby affecting fiber formation . We hope that this work opens up a promising avenue for producing cost-effective, high-yield artificial silks.”
Referencia: “Artificial superstrong silkworm silk surpasses natural spider silks” by Jingxia Wang, Tiantian Fan, Xi Li, Xiaoxia Hu, Weidong Huang, Wensu Yuan and Zhi Lin, 6 October 2022, Matter.