Delft researchers make soft robot grippers move with algae and light

A team at Delft University of Technology has made soft robotic arms that move when algae on their surface photosynthesise, WIRED reported.

The devices have two hydrogel layers, one sensitive to pH. Light-driven changes in the algae's metabolism alter local acidity, causing that layer to swell or shrink and bend the arm. The devices are about three-quarters of an inch long and roughly credit-card thickness.

The researchers demonstrated a four-finger gripper lifting a hollow metal sphere and a hook-shaped device moving a rubber ring. Although chemical changes began within seconds, substantial bending took several hours.

Research lead Marie-Eve Aubin-Tam said the work explores how living cells can be integrated into functional materials. The team hopes it will inform future environmentally responsive soft robots, including fluid-control and underwater applications.