Long-Term Induced Pluripotent Stem Cell Culture using Automated Cell Culture System. (A) Morphology and corresponding fluorescence of GFP, under the control of the Nanog promoter, of each mouse iPS colony passaged automatically for long-term culture. The mouse iPS cells were cultured for 4 weeks and passaged 17 times. Scale: 100 μm. (B) Quantification of iPS cell proliferation based on colony size by Nanog-GFP expression compared with the first passage iPS cells. (C) Quantification of iPS cell viability based on colony forming frequency by Nanog-GFP expression compared with the first passage iPS cells.