Transparent, Hydrogel-Based Robots Move When Inflated with Water

Engineers have fabricated transparent, gel-based robots that move when water is pumped in and out of them. They are made entirely of hydrogel — a tough, rubbery, nearly transparent material that’s composed mostly of water. Each robot consists of hollow, precisely designed hydrogel structures connected to rubbery tubes. When water is pumped into them, the structures inflate in orientations that enable the robots to curl up or stretch out.