Fig. 1

Induction of a trophoblastic cyst structure in hiPSCs in a micromesh culture. A Schematic diagram showing the procedures for cell seeding and culture in a limited area on a micromesh. (a) Mesh shapes and dimensions. (b) Scanning electron microscope image of a fabricated triangular mesh. (c, d) Schematic showing how cell seeding and culture were performed on mesh sheets suspended in a culture medium. (e) Real product photograph. A micromesh sheet seeded with hiPSCs was placed in a 3.5-cm dish and cultured for 30–50 days. B Time-lapse monitoring of hiPSCs on a 4-mm suspended mesh sheet. Phase-contrast images of hiPSCs on days 16–22 of micromesh culture. Scale bar = 1 mm. C Stereomicroscopic images of hiPSCs in micromesh culture. Scale bar = 1 mm. D Enlarged view of stereomicroscope images, showing numerous cysts in the micromesh culture on day 46. E Quantitative analysis of hCG secretion by ELISA. Culture supernatants were collected from micromesh culture samples. Data are presented as means ± SEMs (n = 4). F Immunofluorescence analysis of cysts. Bright-field and immunofluorescence images of representative cysts stained for hCG. Nuclei were stained with DAPI (blue). Scale bar = 100 μm. G High-magnification images of immunofluorescence for hCG. To scan high-magnification images using a confocal microscope, individual cysts were resected and placed on the cover glass for observation. Scale bar = 100 μm