Culture media, cell cultures and methods of culturing pluripotent stem cells in an undifferentiated state
Provided are novel serum-free culture media which comprise basic fibroblast growth factor (bFGF), transforming growth factor beta-3 and ascorbic acid at a concentration of at least about 50 microgram/ml; ascorbic acid at a concentration range of about 400-600 microgram/ml, bFGF at a concentration range of about 50-200 ng/ml, xeno-free serum replacement and a lipid mixture; the IL6RIL6 chimera at a concentration range of about 50-200 picogram per milliliter (pg/ml); or leukemia inhibitory factor (LIF) at a concentration of at least 2000 units/ml; cell cultures comprising same with pluripotent stem cells such as human embryonic stem cells and induced pluripotent stem (iPS) cells, and methods of using same for expanding pluripotent stem cells in an undifferentiated state using two-dimensional or three-dimensional culture systems; and methods of expanding iPS cells in a suspension culture devoid of substrate adherence and cell encapsulation.
1. A method of differentiating pluripotent stem cells, comprising
(a) culturing SSEA1-negative pluripotent stem cells in a suspension culture, wherein said pluripotent stem cells comprised in said suspension culture are cultured without adherence to an external substrate, wherein said suspension culture comprises a culture medium, said culture medium comprising ascorbic acid at a concentration range of 400-600 μg/ml and basic fibroblast growth factor (bFGF) at a concentration range of 50-200 ng/ml and being capable of maintaining and expanding the SSEA1-negative pluripotent stem cells in an undifferentiated state in said suspension culture for at least 5 passages, and
(b) subjecting said pluripotent stem cells to culturing conditions suitable for differentiating and/or expanding lineage specific cells;
thereby differentiating the pluripotent stem cells.
2. The method of claim 1 , wherein said culture medium is serum-free.
3. The method of claim 1 , wherein said culture medium is devoid of animal contaminants.
4. The method of claim 1 , wherein said culture medium further comprises serum replacement.
5. The method of claim 1 , wherein said culture medium further comprises a lipid mixture.
6. The method of claim 1 , wherein the culture of step (a) comprises at least 95% pluripotent stem cells in an undifferentiated state.
7. The method of claim 1 , wherein said concentration range of said bFGF is 60-190 ng/ml.
8. The method of claim 1 , wherein said culture medium in step (a) is capable of expanding and maintaining said pluripotent stem cells when cultured for at least 5 passages on a soluble extracellular preparation from Engelbreth-Holm-Swarm tumor cells that gels at room temperature to form a reconstituted basement membrane.