Page 65 - IJB-7-2

Ng, et al.
cytokeratin), and endothelial biomarker (CD31 also be a reasonably long tissue maturation duration for the
known as PECAM-1). Here, we focused only on the different alveolar lung cells to interact, proliferate, and
staining of epithelial and endothelial layers as these two differentiate based on prior works [31,60,62-64] .
main layers are representative of the air-blood barrier. From the immunostaining analysis (Figure 5), we
The AT2 cells can undergo trans-differentiation into type observed the presence of all the biomarkers except for
1 alveolar epithelial cells (AT1) and hence, we checked AT-1 biomarkers (aquaporin-5 and caveolin-1) in both
[74]
for the presence of both AT-1 and AT-2 biomarkers in this groups of 3D bioprinted human alveolar lung models
study. We performed immunofluorescence analysis of the cultured under ALI and LLI conditions, respectively.
human alveolar lung models on day 7 as it is deemed to It was reported in an earlier study that the A549 cells

Figure 5. Immunostaining analysis of triple-layered blood-air barrier models (CMECA) cultured under ALI conditions (3 days LLI and 4
days ALI) and LLI conditions at day 7; scale bar: 200 µm.

International Journal of Bioprinting (2021)–Volume 7, Issue 2 61