Watch this invisible robot grab a fish out of the blue-The soft, hydrogel robot is powered by water

An invisible, squishy robotic claw that grabs unsuspecting fish out of the blue is the latest addition to MIT’s collection of weird little soft robots that could one day start swimming, creeping, and slithering among us.

The robotic claw is inspired by glass eel larvae that are nearly invisible, but tough enough to swim long distances. It’s made out of a hydrogel — a polymer gel that’s more than 90 percent water by weight. Light and sound waves pass through it just like they would pass through water, which makes it nearly undetectable underwater, according to a paper published today in Nature Communications.

Usually, hydrogels are too flimsy to move with any sort of speed or force without falling apart. That’s why soft robots are typically made of silicones — but silicones are easy to see. So a team of scientists at MIT figured out a new formulation of chemicals that, when cured with UV light, make much tougher, but still flexible, hydrogel robots.

Dr. Hans C. Mumm