o To overcome these challenges, internist Joan Nichols and her colleagues at the University of Texas Medical Branch have spent years finding ways to engineer a lung from scratch in the laboratory, using donated cells. Theoretically, these lungs could be custom-built for each patient, solving both wait-time and compatibility problems. In early trials, though, these lungs have failed to keep donee animals alive for more than a few hours; the engineered organs couldn’t replicate the complexity of the blood vessels that enable the transfer oxygen to the blood stream. Until now.