Figure 4: The top row shows light microscope images of NCI-H460 3D culture. (a) (Day 1) demonstrates cells (shown by arrows) that surround the scaffold (dark-shaded areas). This can be compared to (b), which shows that at day 14 multilayers of cells cover the scaffold. The bottom row shows images of H&E staining on paraffin sections of 3D culture after 1 week in culture. (c) shows the complete cross section of a scaffold with most of the large clumps located peripherally (magnification 4x). (d) is an example of a big cluster more than 500 μm in diameter, including a nonviable cell centre region (shown by arrow). The clear region that is marked with an asterisk () shows the location of the scaffold that dissolved in xylene (magnification 20x). Scale bars are (a) 100 μm, (b) 200 μm, (c) 1 mm, and (d) 200 μm.