Genetically modified silkworms can produce fiber stronger than Kevlar

Chinese researchers have successfully genetically modified silkworms to produce webs that are 6 times stronger than Kevlar, which is used to make body armor. This is reported by the scientific publication Cosmos, citing a study published in Matter.

Similar to silkworm silk, spider web is a natural polyamide fiber, while nylon and Kevlar are synthetic polyamide fibers. Commercialization of spider webs is problematic due to the limited understanding of the spider spinning mechanism, technical difficulties in the process, and engineering obstacles in low-cost mass production. In addition, spiders are a very difficult species to breed, including due to intraspecific cannibalism.

“Silkworm silk is presently the only animal silk fibre commercialised on a large scale, with well-established rearing techniques,” says lead author and PhD candidate Junpeng Mi. “Consequently, employing genetically modified silkworms to produce spider silk fibre enables low-cost, large-scale commercialisation.”

Mi and his team introduced the web protein genes into the silkworm’s DNA using a combination of CRISPR-Cas9 gene editing technology and hundreds of thousands of microinjections into fertilized silkworm eggs. The researchers also needed to modify the web proteins to interact properly with proteins in the silkworm glands to ensure proper fiber spinning.

The fibers produced by the genetically modified silkworms had exceptionally high mechanical characteristics.

Besides being used in smart materials for the military and aerospace industries, such fiber can be used in biomedical engineering.

“This type of fibre can be utilised as surgical sutures, addressing a global demand exceeding 300 million procedures annually,” says Junpeng Mi.

Further research aims to create genetically modified silkworms that produce stronger webs from both natural and artificial amino acids.

“The introduction of over one hundred engineered amino acids holds boundless potential for engineered spider silk fibres,” says Mi.