Blocking of collagen/β
integrin interaction inhibits the growth and shell formation of miPSC-derived EBs. (A) Morphology of miPSC-derived EBs after treatment with Vc (collagen stimulator), CIS (collagen inhibitor) or β1 integrin blocking antibody. β1 integrin blocking resulted in delayed growth of EBs and a rough edge. (B) Size analysis revealed that the mean diameter of EBs, compared with that of the control group, was larger in the Vc group and smaller in the CIS and β1 integrin blocking groups (*p < 0.05). The data were obtained from five sample EBs per field in 10 fields, and three independent experiments were performed. (C) Phase-contrast and fluorescent micrographs of miPSC-derived EBs grown as hanging drop with or without β1 integrin blocking. Arrows indicate the loose outer layer and the absence of a dense shell. (D) Scanning electron micrographs of 5-day-old EBs with or without β1 integrin blocking. A fibrous ECM coating and a smooth exterior were observed in control EBs (left column). In contrast, the surface topography of EBs with β1 integrin blocking was characterized by a cilium-like structure and the absence of a dense shell-like layer (right column). Scale bars = 200 μm.