I don’t like to admit that there are many things that are as badass in the marine world as sharks, but hagfish definitely give them a run for their money.
Hagfish are primitive, eel-like creatures that spend most of their lives slithering along the ocean floor, scavenging dead and dying fish. They’re spineless, virtually blind, have no jaws and have barely changed over the last 300 million years. They’re not sounding very tough right now, so what makes them so special? Well, hagfish have a sticky trick up their sleeves. When attacked or threatened, they exude a gelatinous slime into the water that can quickly smother the gills and mouth of a predator, thwarting the attack. This incredible goo has amazed scientists for decades, but we’re only just starting to understand its wonderful properties.
Hagfish slime is formed when seawater interacts with two different ingredients secreted by slime glands: mucin vesicles, which rapidly swell and burst in seawater, forming a gloopy net of mucus strands, and threads that are rich in a type of fiber called an intermediate filament (IF). These individual IF threads, which are produced by gland thread cells (GTCs), are only 12 nanometers in width but up to 15 centimeters in length. They’re arranged in yarn-like bundles called skeins which consist of around 15 to 20 conical layers of loops. As GTCs mature, the threads gradually increase in size, but they are organized in such a way that they can rapidly uncoil without tangling. When the skeins come into contact with seawater, the protein glue holding them together dissolves, causing them to unravel and release the elastic energy stored. This transforms a mere teaspoon of slime into a beaker-full of the stuff in just a few seconds.
Now that scientists are starting to understand the secrets of the slime, companies are attempting to synthesize it in the lab to create new super materials with a wide range of applications. One startup company for example, Benthic Labs, turned to the Hagfish with the ultimate goal of developing a biodegradable polymer made out of components of the slime itself. They think the slime could be used in everything from protective clothing to food packaging, bungee cords to bandages. That’s because hagfish slime threads have some impressive properties; they might be 100 times thinner than human hair, but they’re 10 times stronger than nylon.
To produce these materials, Benthic Labs intend on inserting hagfish DNA for the filament proteins into bacteria, transforming them into filament-producing factories. However, hagfish slime isn’t as strong as it is purely because of the filament proteins- lots of other factors are also involved. Furthermore, the unravelling process needs seawater. If the team can get around this requirement, then they may have a few interesting applications on their hands, such as airbags.