An embryonic stem cell is a pluripotential cell derived from an early embryo cell mass, usually from fertilisation outside a woman's body in a clinic or laboratory.
Culturing embryonic stem cells
As the cells divide and multiply in number, they are separated and replated so that many millions of cells can be derived from the original. When such re-plated cells show no sign of differentiating into any particular tissue, they are referred to as pluripotent stem cells. At any stage such cells can be frozen and transported to other laboratories. When the cells are needed for therapy they can be triggered into differentiation into more mature cell types.
High quality clinical grade human embryonic stem cell lines derived from fresh discarded embryos. Ye J et al. Stem Cell Res Ther. 2017; 8: 128.