FIG. 2.
iPSC-EC network formation is affected by cell ratio and fibrin concentration. Confocal microscopy images of immunofluorescent staining for CD31 (iPSC-EC, red) show formation of vessel-like networks in (A) 25% MSC, (B) 50% MSC, and (C) 75% MSC spheroids encapsulated in 3 mg/mL fibrin and cultured for 3 weeks. (D) No network formation was observed in the absence of MSCs (0% MSC group). (E) Spheroid encapsulated in 1 mg/mL fibrin formed flat sheets expanding through the gel. (F) Spheroid encapsulated in 1 mg/mL fibrin formed thin sprouts with no visible lumen. In all images, scale bar represents 200 μm. EC, endothelial cell; iPSC, induced pluripotent stem cell; MSC, mesenchymal stem cell. Color images are available online.
