Engineering Dynamic 3D Models of Lung.

The lung parenchyma-consisting of gas-filled alveoli, vasculature, and connective tissue-is the site for gas exchange in the lung and plays a critical role in a number of chronic lung diseases. In vitro models of lung parenchyma can, therefore, provide valuable platforms for the study of lung biology in health and disease. Yet modeling such a complex tissue requires integrating multiple components, including biochemical cues from the extracellular environment, geometrically defined multicellular interactions, and dynamic mechanical inputs such as the cyclic stretch of breathing. In this chapter, we provide an overview of the broad spectrum of model systems that have been developed to recapitulate one or more features of lung parenchyma, and some of the scientific advances generated by those models. We discuss the use of both synthetic and naturally derived hydrogel materials, precision-cut lung slices, organoids, and lung-on-a-chip devices, with perspectives on the strengths, weaknesses, and potential future directions of these engineered systems.