Fig. 3.

Growth of human embryonic stem cells in different feeder layers. a Human embryonic stem cells on an MEF feeder layer have a clear colony border, but the colony does not show a clear clustering of cells and is flat (20×), b human embryonic stem cells on a HFF feeder layer have a clear colony border, but the center of colony differentiates easily (20×), and c human embryonic stem cells in a mixed feeder layer (MEF: HFF = 1:1) have a clear colony border and apparent limitation to surrounding cells, the colony is thick (20×)