While the big long bones of our body have secondary functions in generating blood cells, most bones in our body have the simple function of support or protection. Imagine, after MRI and CT scan, having a complex file with all the specs of each of your bones, ready for surgeons to upload. If some terrible tragedy were to befall you and suddenly you needed a new shoulder blade (scapula), imagine being able to reprint one for the surgeon to stick back in your shoulder.
A team at the University of Washington (along with others around the world) has developed an initial “bone recipe” comprised of bone meal, powdered sugar and malodextrin (another sugar). This would be loaded into a printer and layered until the proper bone was created. Most attempts so far have focused on the skull as these need a very specific size (so it doesn’t push on the brain) but also because it does not play an intricate role in muscle movement like that scapula or a femur.
In the future though, the idea of Luke Skywalker having his arm replaced doesn’t seem that out of the question.