MIT engineers have developed transparent hydrogel robots that are fast and strong enough to capture live fish. The hydrogel is shaped using laser cutting and 3D printing and can be controlled by injecting water through hollow channels in the structure. The water injection method allows for faster and strong motion than similar designs that are powered by osmosis.
In a striking demonstration of the technology, the team fabricated a hand-like robotic gripper and pumped water in and out of its “fingers” to make the hand open and close. The researchers submerged the gripper in a tank with a goldfish and showed that as the fish swam past, the gripper was strong and fast enough to close around the fish.
The properties of the hydrogel material also allow the robots to be virtually invisible underwater, as demonstrated by placing a hydrogel robot fish against a multicolored background.