Human embryonic stem cell colonies that have been stained for alkaline phosphatase (red). Alkaline phosphatase staining is used to show that the colonies are pluripotent. The colonies are growing on a layer of mouse embryonic fibroblasts which help sustain growth and pluripotency of the stem cell colonies.
Biological Process: Pluripotency
Author: Yuhuan Wang
Source: The Cell: An Image Library