Fig. 4.

Culturing primary human umbilical vein endothelial cells (HUVECs) on top of (a, d) and within 3D fibrin matrices (b, c, e). a) HUVECs attached to fibrin matrices at 3 h. b) HUVECs in 3D fibrin matrices at 30 min and 48 h. Red and black arrows point to apoptotic and live cells respectively. c) Live and dead cells at 48 h. d) Cells attached to the fibrin matrices were quantified with alamar blue assay. e) Cells in 100 μl fibrin matrices at 48 h were quantified with alamar blue assay. Cell numbers are related to the initial seeded cells. ***: p < 0.001 and ****: p < 0.0001.