When a bone break is too severe to heal on its own, surgeons often rely on grafts or rigid metal implants — but both come with serious drawbacks. Now, researchers at ETH Zurich have created a jelly-like hydrogel that mimics the body’s natural healing process, offering a potentially game-changing alternative. Made of 97% water, this soft material can be laser-printed into intricate bone-like structures at record-breaking speeds, down to details thinner than a human hair.