Fig 1: Alveolar type 2 cell culture after organoid-based expansion on insert and Alveolus Lung-Chip platform. Organoids from donors at different passages were dissociated, mixed and seeded on inserts or the Alveolus Lung-Chip and cultured for 7 days. A: fluorescent images of AEC2s after 7 days of culture on inserts or chips, in presence or absence of stretch. Cells were fixed and stained for HTII-280 (AEC2s, green), prosurfactant protein C (SP-C, red), and nuclei with DAPI (blue). Representative image from n = 4 independent experiments with different donor (mixes). B: the same cultures represented in A were furthermore stained with zonula occludens-1 (ZO-1, green), or C: surfactant proteins A (SP-A; red) or B (SP-B; green). D: at day 7, culture cells were lysed and RNA was isolated followed by cDNA synthesis to assess gene expression levels of surfactant protein B (SFTPB) and C (SFTPC). Data are shown as delta Ct normalized for the geometric mean of the reference genes OAZ1 and ATP5B. Cultures on inserts are indicated with blue dots, chip control cultures with yellow dots and chip cultures exposed to 5 days of stretch with orange dots. The comparison between insert and chips was performed with three different donors. The comparison of stretch application with the control chip was performed with six different donor (mixes). AEC2s, alveolar type 2 cells.