Fig. 1

Schematic and photograph of the 2D and 3D culture system. a The schematic of conventional 2D flask. b The general schematic of the hollow fiber bioreactor-based 3D culture system. The system was composed of a pulsatile perfusion pump, an oxygenator, a cartridge containing thousands of hollow fibers, a bottle of culture medium, and the connecting tube. c A general schematic of cross-sectional view through the bioreactor. d The photograph of our 3D culture system