Spider silk is prized for its unrivaled strength and toughness. Figuring out a way to mass produce it is a challenging task. Spiders can’t be put to work to produce fibers like silkworms can. They’re extremely territorial and inclined to eat their neighbors, and the spiders will refuse to work for too long. So for decades, scientists have tried to genetically- engineer various organisms including bacteria, yeast, mice, hamsters, and even goats, to produce spider silk with no real success. 

For the first time, researchers from China have coaxed pure spider silk from genetically modified silkworms. This material is six times as tough as the Kevlar used in bulletproof vests. The strands are not as strong or stretchy as natural spider silk, but they are advanced. 

In the new study, the researchers used the gene-editing tool CRISPR/Cas9 to insert the complete instructions for making spider silk protein into silkworms and make sure the protein wound up in the silkworms’ silk-making glands. That allowed the team to take advantage of the insect’s natural machinery. Breeding the silkworms resulted in some that inherited the spider silk gene from both parents, meaning they could produce purer spider silk.

The researchers would also confront the same challenges of traditional silkworm farmers, including ensuring that insects’ are healthy. Another spider silk researcher at Utah State University notes that silkworms are notoriously vulnerable to infection. 

Silkworms still make one of the most attractive candidates for this type of genetic engineering. Moving forward, researchers hope to develop even stronger and stretchier fibers by incorporating artificial amino acids into the spider silk protein.