Fig. 1: The Human alveolus chip.

a Schematic of human alveolus chip with primary alveolar epithelial type I (ATI) and type II (ATII) cells lining the upper surface of the porous ECM-coated membrane in the air channel with and pulmonary microvascular endothelial cells (MVEC) on the lower surface of the same membrane in the basal vascular channel that is continuously perfused with medium. The entire membrane and adherent alveolar-capillary interface are exposed to physiological cyclic strain by applying cyclic suction to neighboring hollow chambers (gray) within the flexible PDMS microfluidic device. b Two magnifications of immunofluorescence micrographs showing the distribution of ZO1-containing tight junctions and ATII cell marker surfactant protein C (SPC) in the epithelium of the alveolus chip (bar, 50 μm). c Graph showing the percentages of ATI and ATII cells at the time of plating and 14 days after culture on-chip. Data represent mean ± SD; n = 3 biological chip replicates. d Immunofluorescence micrographs showing alveolar epithelial cells (top) and endothelial cells (bottom) within the alveolus chip stained for ZO1 and VE-cadherin, respectively (scale bar, 50 μm). e Temporal gene expression profiles in the alveolar epithelial cells on-chip. f Smoothed regressions of time course showing expression of selected genes that are involved in host defense response in epithelial cells cultured for up to 2 weeks on-chip; n = 3 biological chip replicates. Gray zone indicates the 95% confidence interval for predictions from a linear model; green, day 0; blue, day 8; pink, day 14. g Graph showing the mRNA levels of key genes from f in the epithelial cells of alveolus chips at day 1 and day 14 after culture. Data represent mean ± SD, n = 3 biological chip replicates independent of the RNA-seq samples. Unpaired two-tailed t-test. h Immunofluorescence staining showing increased MX1 expression in both alveolar epithelial cells and microvascular endothelial cells on-chip at day 14 compared to day 1 of culture. Scale bar: 50 μm. Source data are provided as a Source Data file.