Evaluation of the iPS cells cryopreserved with Cell Banker 3 after 3 and 12 months of storage. (A) The viability of the cryopreserved iPS cells after 3 and 12 months of storage at −80°C. 1, After 3 months; 2, after 12 months. (B) The proliferation of cryopreserved iPS cells after 3 and 12 months of storage. 1, After 3 months; 2, after 12 months; 3, only the MEF feeder cell layer. The data are the means and SD of three independent experiments. (C) The phase-contrast photomicrographs of (1) cryopreserved iPS cells after 12 months. The fluorescent photomicrograph (2) exhibited the expression of green fluorescent protein derived from undifferentiated iPS cells. (C) Scale bar: 100 μm.