The conventional hESC medium contained 80 % (vol / vol) KnockOut Dulbecco's Modified Eagle's Medium (DMEM) and 20 % (vol / vol) KnockOut serum replacement supplemented with 2 mM Glutamax, 0.1 mM β - mercaptoethanol, 0.1 mM MEM non-essential amino acids (Cambrex Bio Science, Walkersville, Inc., Walkersville, MD), 50 U / ml penicillin - 50 μg / ml streptomycin (Cambrex Bio Science) and 8 ng / ml
recombinant human fibroblast growth factor (bFGF, R&D Systems, Minneapolis, MN).