Human embryonic stem cells are propagated on synthetic substrates. The cells are stained with human pluripotent stem cell markers (Nanog, Tra-1-60, OCT4-GFP, and SSEA4). Image courtesy of Y. Mei, K. Saha, R. Langer, R. Jaenisch, and D.G. Anderson Sep. 3, 2010 Facebook Twitter Reddit Print Human embryonic stem cells are propagated on synthetic substrates. The cells are stained with human pluripotent stem cell markers (Nanog, Tra-1-60, OCT4-GFP, and SSEA4). Image courtesy of Y. Mei, K. Saha, R. Langer, R. Jaenisch, and D.G. Anderson