Fig. 2
ECM promotes the attachment and CFU-F formation of UCB-NHSCs. a MNCs were isolated from UCB using a Ficoll-Paque Premium density gradient, seeded (1 × 106 MNCs/cm2) onto either extracellular matrix (ECM) or uncoated tissue culture plastic (TCP), and incubated at 37 °C for up to 72 h as described in the Methods. At harvest, non-adherent cells were removed by washing with PBS and cell attachment to the surfaces recorded photographically under phase contrast microscopy. Scale bar = 100 μm. b Colony-forming units fibroblast (CFU-F) colony formation by primary (P0) cultures of MNCs on ECM or TCP surfaces. CFU-Fs were fixed and stained with crystal violet. Scale bar = 100 μm. c Phase contrast microscopy of CFU-Fs in culture. Some areas of the cultures have the appearance of embryonic bodies (EB). Scale bar = 10 μm. d OCT4, a marker used to identify ES cells, was expressed by EB formed by the UCB-NHSCs in culture. OCT4 was detected by immunofluorescence. Non-specific isotype IgG was used as a negative control (Neg. cont). Nuclear staining with DAPI is shown in blue. Scale bar  = 10 μm