(A) Phase contrast micrographs of C32 iPSCs prior to and following seeding into HDMA. Scale bars: 200 μm. (B) Phase contrast micrographs of C32 iPSC-CMs from 15 d cardiac differentiations, prior to and following HDMA seeding. Scale bars: 200 μm. (C,D) Plots of the distribution of fixed, Hoechst-labelled HES3 hESCs after injection into HDMA at 2 × 106cells/mL. Image fields containing 6 HDMA chambers (three rows of one column pair) were acquired and nuclei counted by image cytometry. Images fields were taken from the top (Rows 01-03), middle (Rows 25–27), and bottom (Rows 48–50) section of the device, and from each of the 81 column-pairs. Average numbers of cells detected per field of 6 chambers is shown, averaged along column pair (C; n = 3 row groups) and row group (D; n = 81 column pairs). Bars represent mean ± S.D. and data from one experiment is shown to highlight the variation present within an individual HDMA.