2.12 Cell viability and proliferation
The cell viability was assessed using a by live/dead viability/cytotoxicity kit (Invitrogen, USA). Briefly, the vascular structure was washed 3 times with DPBS, and then incubated at 0.5 μL/ml Calcein AM and 2 μL/ml ethidium homodimer for 45 minutes. Laser confocal microscopy (LSI, Leica, Germany) was used to observe the living and dead cells in the structure. Six random views were selected to evaluate the cell viability using Image J.
CCK-8 (Sigma-Aldrich, USA) was used to detect the cell proliferation in the vascular structure. These vascular structures were transferred into a 24 well plate. 900 μL fresh medium and 100 μL CCK-8 solution were added. After incubated at 37℃ for 3 hours, 100 μL solution was transferred into 96 well plate and the ODs were read by spectramax M5 at 460nm.