|
 When attacked or threatened by a predator the marine creature
defends itself by secreting a milky-white substance from its glands.
This instantly reacts with the seawater around it to form a mass of
slime that clogs the mouth and gills of the would-be attacker.
But this slime has special properties that could benefit mankind,
according to scientists from ETH Zurich (Swiss Federal institute of
Technology).
Hagfish slime is an extremely diluted hydrogel, consisting of over
99.99 percent water. Hydrogels are used in a multitude of everyday
products including diapers, moisturisers and contact lenses. But
hagfish slime is more efficient and fast-forming than other types of
hydrogel, such as conventional animal gelatin.
 "Hydrogels are present in many everyday products; from diapers to
face creams to food materials. And by studying the slime, we're
trying to find out how we can make super hydrogels, so hydrogels
that can entrap large amounts of water," said PhD student Lukas Böni.
The glandular secretion the hagfish produces when attacked is made
from mucin vesicles and tightly coiled skeins of protein measuring
just 150 micrometers in diameter. When released by the hagfish they
quickly interact with seawater; the mucin vesicles releasing a
saliva-like substance and the skeins unwinding into long threads.
Together they form a matrix of slime that can disable much bigger
marine animals.
How the coiled thread unwinds with such speed and efficiency when it
comes into contact with seawater is still a mystery the team is
working to understand.
"One protein thread is coiled up into one skein, and if you extend
this thread it is up to 30 centimeters long. And when these skeins
come into contact with water they unravel and form these long
protein threads, which span a network that together with the mucin
entraps the water," said postdoctoral researcher Patrick Rühs,
adding that the protein threads have a similar property to spider
silk and are extremely tear-resistant and elastic.
[to top of second column] |
The researchers traveled to Norway to collect samples of the
hagfish's secretion before transporting it back to their laboratory
in Zurich.
"We bring in the fish, we sedate them, we blot them dry. And once
they're sedated we put them on a dissection tray and then we mildly
stimulate the ventral side of the fish. This causes the muscles to
contract and the exudate, this glandular secrete, to be expelled,"
said Böni, adding: "After the sampling the fish wakes up again; so
the fish is not harmed by taking the sample."
They are now working to unlock the secret of the slime formation and
its huge capacity to absorb water with the hope of recreating it
artificially in the lab. Böni believes that the hagfish's natural
system is far too complex to completely replicate, but is hopeful
they can develop a gel that follows the principle of the natural
slime.
Similar research from the University of Guelph in Canada has
proposed that the fibers of the hagfish slime could be used to make
textiles.
[© 2016 Thomson Reuters. All rights
reserved.]
Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
