Fig. 4. Adipocyte 3D cell cultures derived by scaffold-free differentiation of hASCs on-chip exhibit mature adipocyte characteristics. A) Overview of the experimental setup for the differentiation of hASCs towards adipocytes. B) Brightfield images of one representative cell culture chamber along the adipogenic differentiation pulse fed every 4 h. Scale bar: 250 μm. C) Validation of adipogenic maturation by lipid droplet staining (BODIPY, green) of cryosections prepared after retrieval of the 3D cell cultures from the chip. Nuclei were counterstained with DAPI (blue). Scale bars: 50 μm. D) Equivalent diameter of the 3D cell culture during the adipogenic differentiation relative to the aggregate size on day 1. n = 4 biological replicates. E) Lipid droplet and nuclei counts over the course of differentiation quantified from the middle section of the 3D cell cultures. n = 2 for day 1, n = 12 for day 8, n = 10 for day 15, *p < 0.05 (one-way ANOVA).