Fig. 2. Assembly and preparation of the SPHEROIDS flight hardware. A, B) The medium chambers were filled with cell culture medium. C, D) The fixation chamber was filled with fixation fluid, PFA or RNAlater. E, F) Medium chambers and supernatant chambers were assembled. G) The experimental unit before adding the cultivation chambers. H) Assembly of modules onto main support. The dimensions of one assembled hardware unit are 10 × 10 × 10 cm. CC: Cultivation chamber, E1: Experiment 1 (−VEGF), E2: Experiment 2 (+VEGF), MC: Medium chamber, SC: Supernatant chamber.