Feeder-independent culture of human embryonic stem cells

We recently reported the development of TeSR1, a serum-free, animal product-free medium that supports the derivation and long-term feeder-independent culture of human embryonic stem cells(1). Although the derivation of new human embryonic stem cell lines in those defined conditions offered an important proof of principle, the costs of some of the defined components in that culture system made it impractical for everyday research use. Here we describe modifications to the medium (mTeSR1) that include the use of animal-sourced proteins (bovine serum albumin (BSA) and Matrigel) and cloned zebrafish basic fibroblast growth factor (zbFGF). We include a simple protocol that allows purification of up to 100 mg zbFGF in less than three days (Fig. 1), an amount sufficient to make 1,000 I of mTeSR1 medium. The modifications presented here make mTeSR1 practical for routine research use, and the protocols presented are those currently used in our laboratory for standard human embryonic stem cell culture.