We have developed an airway barrier microphysiological system incorporating bronchial epithelial cells which recapitulates interstitial flow of the in vivo tissue microenvironment and can monitor barrier responses in real-time.  Other in vitro cell culture models include fully differentiated epithelial-endothelial, epithelial-fibroblast and epithelial-mast cell co-cultures to determine cross-talk between the bronchial epithelium and underlying structural or immune cells following environmental challenges. Cells used in these studies are from cell lines, healthy individuals and patients with asthma.