Bioengineer Shaochen Chen has developed a method of 3D printing live human tissue that could one day be used to heal damaged spinal cords, hearts, and other vital organs. And, because his technology uses stem cells, the transplant tissue can be patient specific. Now, he's using his technique to help researchers Alysson Muotri and Karl Wahlin understand brain and eye development. Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 34336]