This is way over my head but it's amazing what they're able to do with the technology.
"Bioprinting involves using a person’s own body cells to reconstruct an organ. Three-dimensional bioprinting, like other forms of 3D-printing, involves adding layer on top of layer of a material to create a complete structure." Read the article:
First 3D-Printed Blood Vessels Bring Scientists A Step Closer To Bioprinting Human Organs By Philip Ross, IBT June 02 2014