Figure 4: Culture of piPSC in feeder free conditions. Live stained SSEA1+ piPSCs were manually passaged onto Matrigel in one of 7 different media types: mTeSR1, KSRF, KSRFL, KFC, KFP, KFCP and NCP. After 6 passages, immunocytochemistry results showed that piPSCs were strongly positive for the introduced factors POU5F1(A; cells in mTeSR1 shown) and NANOG (B) and non-overexpressed stem cell markers SSEA1(C), SSEA4 (D), TRA-1-60 (E) and TRA-1-81 (F) in all conditions. Flow cytometry analysis of cells at passage 6 showed that >75% of cells were SSEA1+ (G) and >20% being SSEA4+ (H) in KSRF, KSRFL and KFP conditions. mTeSR1, KFC, KFCP and NCP conditions showed significantly lower levels of SSEA1+ cells and mTeSR1, KFC, KFCP conditions showed significantly lower SSEA4+ cells. Bars which are not denoted by a common letter (a-d) show a statistically significant difference, p-value<0.05.