sciencehabit quotes a report from Science Magazine: If you shatter a bone in the future, a 3D printer and some special ink could be your best medicine. Researchers have created what they call "hyperelastic bone" that can be manufactured on demand and works almost as well as the real thing, at least in monkeys and rats. Though not ready to be implanted in humans, bioengineers are optimistic that the material could be a much-needed leap forward in quickly mending injuries ranging from bones wracked by cancer to broken skulls. Researchers at Northwestern University, Evanston, in Illinois are working on a hyperelastic bone, which is a type of scaffold made up of hydroxyapatite, a naturally occurring mineral that exists in our bones and teeth, and a biocompatible polymer called polycaprolactone, and a solvent. Hydroxyapatite provides strength and offers chemical cues to stem cells to create bone. The polycaprolactone polymer adds flexibility, and the solvent sticks the 3D-printed layers together as it evaporates during printing. The mixture is blended into an ink that is dispensed by the printer, layer by layer, into exact shapes matching the bone that needs to be replaced. The idea is, a patient would come in with a nasty broken bone -- say, a shattered jaw -- and instead of going through painful autograft surgeries or waiting for a custom scaffold to be manufactured, he or she could be x-rayed and a 3D-printed hyperelastic bone scaffold could be printed that same day.