Fig. 1.

Lung engineering includes three main components, including (A) an organ-specific scaffold, (B) appropriate numbers and types of cells, possibly obtained from the patient that requires the organ, and (C) a bioreactor in which to cultivate the tissue or organ (C). The leading source of scaffolds is currently a decellularized extracellular matrix scaffold, while the optimal cell source has yet to be determined. iPS cells and fetal-associated cells may be more tractable for the clinic due to fewer ethical hurdles that has led to greater access to these cell types. iPS cells have the additional benefit of fewer potential immunological complications. An effective bioreactor must provide physiological stimuli and support active cell growth.