Figure 3.

Images of EHM rings taken 24 h after casting the gel using different cell densities (A–D): 100; 200; 400 and 2000 CF cells/μL using a 1 mg/mL collagen concentration. The images show the top view of the EHM-rings within the clear silicone mold on a black background with white grid (1 cm by 1 cm). Surrounding the central pole is a light pink circle, most left vaguely showing, becoming clearer with increasing the cell density; The final image (E) shows the EHM-ring (8000 cells/µL, 1 mg/mL collagen concentration) after 7 days of culturing, next to the central pole. The EHM ring has been removed from the central pole manually to enhance visibility. Bars represent 2 mm.