Sharks are the greatest hunters in the water, on TV and in the movies (aren’t we glad they can’t walk?) and the tools of their trade have been studied for years in vain attempts by humans to learn their secrets. Perhaps its time to study sharks for their other abilities. New research has found that shark jelly – a mysterious gel (not the edible kind) it uses for hunting - is also the best proton conductor in the natural world.
Shark jelly is found in the ampullae of Lorenzini (named for the 17th century ichthyologist Stefano Lorenzini). Ampullae are pores in a shark’s skin which lead to jelly-filled canals that are connected to electrosensitive receptors. It’s this system that allows sharks, skates, and rays to detect prey via their bodies’ weak electric fields.
In an attempt to figure out how this works, researchers from UC Santa Cruz, the University of Washington, and the Benaroya Research Institute at Virginia Mason focused on the mysterious clear jelly and learned it has the highest proton conductivity ever observed in a biological material. According to their study in Science Advances, the scientists found the conductivity of shark jelly shocking, says co-author Erik Josberger.
The first time I measured the proton conductivity of the jelly, I was really surprised. I didn’t expect a natural material to approach the proton conductivity of an engineered material like Nafion.
Nafion is the top synthetic proton-conducting polymer and a key component in fuel cells, electrochemical devices and devices and sensors used in metal-ion recovery, water electrolysis and a number of other applications. Proton conductivity – the ability to transport positive hydrogen ions – in thin membranes is the key to making inexpensive fuel cells.
Are you impressed by shark jelly? Erik Josberger is.
Given that Nafion is a very carefully prepared material that's very precisely made, it was interesting to see the shark had replicated something very close to that material just by nature.
There aren’t enough sharks left to harvest shark jelly to meet the world’s proton conductivity needs, so the researchers are hoping to develop a synthetic version with the same properties.
The Ampullae of Lorenzini would make a great name for the villainous species in my next sci-fi novel.