Figure 5.

One of the main limitations of the hollow fiber is their optical property that does not allow intralumenal inspection during an experiment. However, after immersion for a few minutes in mineral oil used for microscopy, the fibers become transparent (A) and can be visualized by confocal (B) or light (C) microscopy. The cells in (B) are endothelial in the lumen of the hollow fiber (h.f.) and astrocytes in the ablumen; both were colored with a red cell tracking dye. In (C), cresyl violet staining of sparse endothelial cells 1 h after plating is shown.