Figure 5.

Structural and functional characterization of 3D inkjet‐printed alveolar barrier model. a–d) Immunofluorescence microscopic images using specific antibodies (green) and nuclei staining reagent Hoechst33342 (blue); the endothelial marker CD31 derived from HULEC‐5a cells (a), the basement membrane constituent collagen IV and laminin resulted from cell‐ECM interaction (b), the tight junction protein ZO‐1 which presents a solid intercellular connection (c), and hydrophilic surfactant SP‐A secreted by type II alveolar cells (d). Scale bars: 50 µm. e) Microscopic cross‐section image after Alcian blue and nuclear fast red staining. Nuclei in cells and the secreted surfactant are stained in purple and light blue, respectively. The arrows indicated newly produced surfactant in the epithelium layer. Scale bars: 20 µm.