Fig. 2.

Morphological changes induced by exposure to nanomaterials in 3D human lung microtissues. a Primed THP-1 cells are exposed to nanomaterials prior to mixing with fibroblasts and epithelial cells as described in the Materials and Methods. Histopathology of 3D lung microtissues sections following exposure to nanomaterials for 4 days (b) or 7 days (c). Mitotic figures can be seen in untreated microtissues after 4 and 7 days, as illustrated in image insets. Microtissues exposed to carbon nanotubes have altered microtissue morphology, with large nanoparticle aggregates. Focal cell death (black arrowheads) was observed following exposure to carbon nanotubes and asbestos fibers. Sections were stained with hematoxylin and eosin. Scale bar = 50 μm