Kids aren鈥檛 the only ones who love slime. The聽US Navy wants to take the gloopy hobby to the next level 鈥� by making super-expanding weaponised slime that can trap boats in the water.
Currently, the US Navy stops boats 鈥� particularly suspected smugglers 鈥� by using a pneumatic launcher that fires a plastic rope designed to get tangled up in the boat鈥檚 propeller.
But it is not very environmentally-friendly and is hard to disentangle once fired. Instead, a synthetic version of slime could halt small boats by fouling their propeller and then simply dissolve away later.
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Justin Jones and his team at Utah State University have a fifteen-month Navy contract to experiment making slime proteins with this in mind.
They are working on making a usable slime that is inspired by the hagfish, an eel-like creature which deters attackers by projecting a jet of slime, clogging the predator鈥檚 mouth and gills.聽 When it comes into contact with sea water, the slime swells by a factor of several thousand and one hagfish can produce several litres.
Sticky business
Hagfish slime has two components, a sticky mucin and long thread-like proteins. The protein threads provide the toughness and elasticity, thanks to a pattern of repeating proteins similar to spider silk. Jones says they are using modified E.coli bacteria to produce the proteins, a technique honed by the lab鈥檚 twenty years of research on artificial spider silk.
The aim is to move from a labour-intensive process making a few grams at a time to an automated system turning out industrial quantities. The team will then work on spinning the proteins into fibres, again using experience from spinning recombinant spider silk proteins.
of the Nanyang Technological University in Singapore, has been working with hagfish slime proteins, and says the Utah project faces two challenges. One is producing the proteins in large enough quantities, the other is getting the proteins to assemble themselves into threads.
鈥淢y lab demonstrated last year that we can induce this so-called self-assembly, forcing the protein components to wrap around together to make the fibre strong, but that鈥檚 not straightforward,鈥� says Miserez. 鈥淎t scale that will be a challenge.鈥�
Jones is aware it won鈥檛 be easy.聽 鈥淭he devil is in the details, as it is with spider silk,鈥� he says.
As well as smugglers, a slime barrier could also protect against small suicide boats, like the one which struck the USS Cole in 2000. Houthi rebels in Yemen have been known to use unmanned suicide boats against shipping, for example.
