Most robot limbs aren't exactly kind to the organic world given all that unforgiving metal, and even rubber-based soft robots aren't very gentle. However, MIT has a better way. It recently built a hydrogel-based soft robot hand that's bio-friendly while remaining tough enough to withstand heavy use. The trick was to use 3D printing and laser cutting to weave hydrogel "recipes" into robotic structures, and pump water into those structures to make them curl or stretch. The results are mostly water-based fingers that still have the strength, durability and speed of more conventional robots.