Cell maturation is the process of cells maturing and specializing, losing their ability to split and become new cells. 

Pluripotent stem cells have the ability to become any cell in the human body. These cells form other cells, and through development, become specialized to a specific task. For example, once a pluripotent stem cell specializes to become a blood cell, this blood cell has matured and will only be able to be a blood cell from that point forward.