The idea of regrowing limbs sounds "kind of Star Trek-y," Russell admits, but he says that it's within the grasp of science. He points to his colleague at McGowan, Stephen Badylak, a pathologist and fellow AFIRM researcher, who shocked the medical world last year when he reported that a powder culled from pig bladders helped resprout the severed fingertips of two patients in their 60s. Normally, when a person loses a limb, scar tissue forms over the wound, leaving a permanent stub. The pig powder contains signaling molecules that attract cells and proteins known as growth factors and override the scarring process, telling the cells to grow instead. (Badylak settled on pigs because their molecules are similar to those found in humans and easy to obtain.) The pig dust was so effective that, with just a light dusting every other day for two weeks, the fingertips grew back entirely—fingernails and all—six weeks later, Badylak reported. For already scarred-over limbs, researchers have developed an enzyme that eats away scar tissue so they can dust the healthy cells below. With AFIRM's backing, Badylak next hopes to figure out how to stimulate the growth of more complicated muscle tissues found in arms and legs.