2.10 Cell culture
Human umbilical vein endothelial cells (HUVECs, Lonza, MD, USA) were
cultured in EGM-2 (Lonza, USA) and smooth muscle cells (SMCs, Lonza, MD,
USA) were cultured in smooth muscle cell growth medium 2 (Promocell,
USA). Both media were added with 1% v/v penicillin and streptomycin
antibody and the cells were cultured at 37 ℃, 5% CO2,
and 95% relative humidity. 1:1 EGM-2 and smooth muscle cell growth
medium were mixed for culturing the printed vascular structure, and the
mixed medium was changed every two days. HUVECs and SMCs used in all
experiments were in 4 to 8 generations.