Blood vessels Method: 3-D printer When: 5 years Gabor Forgacs, a tissue engineer at the University of Missouri, is making blood-vessel networks by culturing three types of vessel cells and loading them into a fridge-size bioprinter. This machine prints out the cells to build capillaries in preprogrammed patterns. Liver Method: Grown using stem cells from umbilical-cord blood When: 15–25 years Colin McGuckin has made silver-dollar-size, functional “mini livers.” They aren’t large enough to do a full body’s worth of work, because livers have hard-to-replicate ducts with specialized cells. Kidney Method: Grown on a polymer framework When: 10–20 years His artificial bladder breakthrough in 2006 grabbed all the headlines, but Anthony Atala of the Wake Forest Institute for Regenerative Medicine is forging ahead on other artificial organs. In 2002, when he transplanted artificial kidneys into cows, the organs survived for months and even produced their own urine, albeit not very efficiently. But to build one for humans, he has to figure out the precise combination of seeder cells that will transform a lab-built scaffold into a fully functioning, transplantable organ.
