For achievement of regenerative medicine, ex vivo expansion of stem cells which can be differentiated to various cells is very important. However, it is very difficult to efficiently and safely culture some stem cells such as hematopoietic stem cells in cord blood or human embryonic stem cells. Therefore, the culture systems are investigated by many researchers. Here the state-of-arts of culture of stem cells and in particle development of biomaterials or expansion of stem cells is discussed.