What the scientists did first was to use detergents and other chemicals to wash out all the old heart cells from rat and pig hearts, explained lead investigator Doris Taylor, who is director of the center. What was left was a scaffold of tubes that once were the organ's blood vessels. Stem cells were then injected into that scaffold, where they were supplied with nutrients that allowed them to grow to create a new organ. Within eight days, the hearts were pumping. The basic technology is not new, Taylor said. It is being used to create many of the heart valves that are implanted in current operations, she said. However, heart valves are relatively small. "We have done it on the scale of a pig heart, which is the size and scale of a human heart," she said. "A human heart would be the next step, but we want to perfect the technique first." Read more at: http://news.yahoo.com/s/hsn/20080114/hl_hsn/biotechnologybuildsanewheart