ESC derivation medium.

Reagent	Amount	Final concentration
KnockOut DMEM (Gibco#10829–018)	76 mL
KnockOut serum replacement (KSR) (Invitrogen#10828–028)	20 mL	20%
PeniciHin-streptomycin (100 x) (Gibco#15070–063)	1 mL	1 ×
l-Glutamine (200 mM) (Gibco#25030)	1 mL	2 mM
MEM non-essentials amino acids (100 ×) (Gibco#11140–050)	1 mL	1 ×
β-Mercaptoethanol (10 mM) (Sigma#M7522)	1 mL	0.1 mM
Supplements
GSK3 inhibitor CHIR99021 (10 mM) (Stemgent#04–0004)	30 μL	3 μM
MEK inhibitor PD0325901 (10 mM) (Stemgent#04–0006)	10 μL	1 μM
LIF (107/mL) (Millipore#ESG1106)	10 μL	103/mL

Filter and store the medium (final volume 100 mL) at 4°C and use within 2 weeks. Add supplements (GSK3 inhibitor CHIR99021, MEK inhibitor PD0325901, and LIF) to the media during freshly during use of the media. Prepare β-mercaptoethanol 10 mM stock from 14.3 M stock (Sigma-Aldrich M7522) by adding 6.25μL to 9 mL of sterile distilled water.