This question is part of the following Ask The Expert session:
I am assuming that you are working with human pluripotent stem cells and you use Knockout serum replacement (commonly known as KSR). A lot of scientists have moved away from KSR as it is not defined and includes components that are of animal origin. We have a defined medium called Essential 8 medium that is serum free and is widely used by scientists to culture human pluripotent stem cells. I have attached the necessary protocols and a publication for your review. We have designed a protocol that will allow your cells to be weaned off the serum in a gentle way by changing one variable at a time in the culture conditions, so as to not stress the cells too much. Essential 8 medium has 8 components and has been successfully used to culture both human embryonic stem cells and human induced pluripotent stem cells. Cells cultured in this medium have shown to retain pluripotency, ability for trilineage differentiation and maintain a normal karyotype for more than 50 passages. Essential 8 medium can be used with substrates such as Geltrex or vitronectin.
The links below may also be helpful:
Culturing PSCs in Essential 8™ Medium – http://tools.lifetechnologies.com/content/sfs/manuals/feeder_free_PSCs_in_essential8_medium.pdf
Frequently Asked Questions – Essential 8™ Medium and Vitronectin – http://tools.lifetechnologies.com/content/sfs/manuals/FAQ_Essen8_Medium_vitronectin_man.pdf
Scalable expansion of human induced pluripotent stem cells in the defined xeno-free E8 medium under adherent and suspension culture conditions -http://www.ncbi.nlm.nih.gov/pubmed?cmd=Retrieve&dopt=AbstractPlus&list_uids=23973800
Authors: Wang Y, Chou BK, Dowey S, He C, Gerecht S, Cheng L,
Journal: Stem Cell Res (2013) 11:1103-1116