Algae-powered robotic grippers lift objects using light

Delft University of Technology researchers developed soft robotic grippers that use algae and light to grasp and release lightweight objects, WIRED reported. A four-fingered device lifted a hollow metal sphere, while a hook-shaped gripper handled a rubber ring. The devices combine two hydrogel layers, one of which swells or shrinks as algae alter local acidity through photosynthesis and respiration. The difference between the layers bends the arms without requiring changes to the chemistry of all the surrounding liquid. Light is their only external energy source, but significant bending takes several hours. The demonstrated objects weighed far less than a small paperclip.