a) Full device (blue dye for upper chamber volume, red dye for the lower, channeled chamber volume); b) HUVECs at the time of loading (D0, 4x, ph, scale bar 400 μm); c) LIVE/DEAD staining of the cells (green for dead cells, blue for live cells, scale bar 400 μm); d) actin staining of HUVECs inside the device (green for actin, scale bar 200 μm; inset at 40x).