Article · Wikipedia archive · Last revised Jun 3, 2026

KOSR

Within molecular and cell biology, KOSR, knockout serum replacement, is a defined serum-free formulation optimized to grow and maintain undifferentiated embryonic stem cells in culture. It is more stable, more consistent in quality and performs better in the maintenance of undifferentiated status of embryonic stem (ES) and induced pluripotent stem (iPS) cells than fetal bovine serum, previously the standard for nutritive supplementation of ES and iPS cells. KOSR has been shown to be more effective when used in conjugation with knockout-DMEM.

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Jun 3, 2026
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Within molecular and cell biology, KOSR, knockout serum replacement, is a defined serum-free formulation optimized to grow and maintain undifferentiated embryonic stem cells in culture.1 It is more stable, more consistent in quality and performs better in the maintenance of undifferentiated status of embryonic stem (ES) and induced pluripotent stem (iPS) cells than fetal bovine serum, previously the standard for nutritive supplementation of ES and iPS cells. KOSR has been shown to be more effective when used in conjugation with knockout-DMEM.2

References

References

  1. "GIBCO Knockout Serum Replacement from Invitrogen - Biocompare Buyer's Guide For Life Scientists". Archived from the original on 2011-07-17. Retrieved 2025-11-24.
  2. Lee, S.; Oh, S.; Kim, D.; Han, J.; Moon, S.; Lim, J. (2006). "Serum replacement with a growth factor–free synthetic substance in culture medium contributes to effective establishment of mouse embryonic stem cells of various origins". Fertility and Sterility. 86 (4): 1137–1145. doi:10.1016/j.fertnstert.2006.01.056. PMID 16952360.