The gold standard for feeder-dependent PSC culture

Gibco KnockOut Serum Replacement (SR) is a defined, FBS-free formulation designed to replace FBS in feeder-dependent ESC and iPSC cultures. It has been cited in more than 2,000 publications on various PSC-related applications. Offering documentation required for regulatory review, KnockOut SR helps to reduce the burden of qualifying reagents when transitioning from research applications to clinical applications.

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This superior supplement supports:

  • Improved maintenance of undifferentiated ESCs and iPSCs, especially when used with Gibco KnockOut DMEM (Figures 1, 2)
  • Cryopreservation and recovery
  • Directed differentiation with addition of desired growth factors; no need to transition to a different medium

Taking your work to the clinic? Be sure to check out CTS KnockOut SR XenoFree Medium

Bar graph showing the percent undifferentiated mouse ESCs observed when cultured in various combinations of traditional and KnockOut DMEM and ESC-qualified FBS and KnockOut SR. Highest percentage of undifferentiated was achieved with the KnockOut DMEM plus KnockOut Serum Replacement combination.

Figure 1. Undifferentiated ESC growth. Murine D3 ESCs were cultured at low density in DMEM or KnockOut DMEM supplemented with ESC-Qualified FBS or KnockOut SR and traditional supplements. No LIF (leukocyte inhibitory factor) was used. After 7 days, colonies were fixed and stained for alkaline phosphatase, a marker for undifferentiated ESC. Undifferentiated colonies were scored based on morphology and staining characteristics.

Phase contrast image shows iPSC colonies with normal morphology, surrounded by MEFs.

Figure 2. Phase contrast image of iPSCs grown in KnockOut SR. iPSC colonies were grown in 20% KnockOut SR, DMEM/F-12 with GlutaMAX supplement, 4 ng/mL Gibco bFGF, and 100 µM 2-mercaptoethanol on mitotically inactivated mouse embryonic fibroblasts. iPSC were passaged with the StemPro EZPassage Disposable Stem Cell Passaging Tool.

Complete media system

Supplement Basal medium Recommended reagent
KnockOut Serum Replacement
DMEM/F-12 or KnockOut DMEM