The Jawless Fish that Inspires Biotechnologists
It's not just spiders that have been found to produce extremely strong material. If we want to find another specialist, we must dive deep into the ocean.
Jawless, eyeless, eel-like animals that mainly feed on dead whales, hagfish (class Myxini) have been around for at least 300 million years. A 2019 discovery of a 100 million fossil reveals more information about their ancestry. Hagfish branched off the vertebrate evolutionary tree with lampreys about 500 million years ago! They gracefully survived mass extinctions, such as that of the dinosaurs. What is their secret of success?
Although it quite likely didn't help them survive the extinctions, these primitive and spineless creatures produce slime which they exude when threatened. The attacker ends up covered in it and has to back off, shocked about what happened, as the slime possibly also clogs the attacker's gills!
It's not just a simple goo. Around one hundred glands produce the milky substance which, when mixed with sea water, creates a huge amount of slime that consists of very thin and extremely strong and stretchy fibers, that can choke a predator. These fibers become a silky, threadlike material when dried out.
This is how hagfish utilize their slime in predator avoidance.
Hagfish threads are around 100 times thinner than human hair, and 10 times stronger than nylon. They could be used instead of synthetic fabrics such as nylon and polyester, which are made from petroleum. This would be a green, renewable and natural solution.
However, it would be pretty hard to get enough slime from hagfish to produce super-clothes, it would be expensive, and not really animal-friendly. Therefore scientists are looking into genetically engineering bacteria to produce this slime protein. In the past years, numerous studies have aimed to pinpoint how exactly the material is produced by the hagfish, as well as how it can be created in labs.
"If we can find better mechanisms to process natural materials into fibers, then either slime or spider silk could be our next generation of high-performance materials," said Christopher Holland of the Oxford Silk Group at the University of Oxford.
That's a lot of slime.
