How are Stem Cells Studied?
Scientists study the properties of stem cells by maintaining them in small shallow laboratory dishes (such as the Petri dish). The stems cells are put in a dish and covered in a liquid, called culture medium, which contains nutrients that the stem cell needs to survive and grow. This is a stem cell culture.
Many types of cells can be cultured in this way. But stem cells are particularly good at being kept in culture: they divide readily, and can continue to do so for long periods of time.
Once the stem cells are cultured, scientists then manipulate the culture environment. They do this by adding or subtracting different chemicals (called factors) from the culture medium. Doing this systematically allows us to learn which factors are necessary and sufficient to direct a stem cell to turn into each of the different types that we find in the human body.