It sounds like science fiction, but researchers from the University of Missouri have a 3D printer that could one day recreate human organs by using a cocktail made from human cells. If your liver was failing, for instance, cells from your liver could be used to print a healthy one, or cells from your heart could be used to create a new heart, and so on.
Right now, all of that is still a long way off. What has been done, however, is recreate a human vein using "bio-ink," or the liquid sludge that's produced using human cells and printed onto "bio-paper." This paper slowly dissolves as the layers of ink bind and start to take on the shape us humans would recognize.
Gabor Forgacs, the man who created the Organovo NovoGen prototype printer, told NPR that the blueprints for the organs, or "schemes" as he calls them, can be created using x-ray technology and the like, giving researchers an outline and floor plan to each organ. It's not as simple as it sounds, though, and you probably won't hear about printed organs replacing a failing liver. Human testing could begin within five years, according to Forgacs, whose team is currently perfecting the process to print out a human vein.
Each vein starts as a series of circles and then, like layering flattened donuts one on top of the other, the entire stack creates a cylinder — a vein.
NPR has an interview with Forgacs you can listen to here.