Three-dimensional culture of human neural stem cells, F3-effluc, within the soft and stiff GPT hydrogels. (a) In the bottom of the 24-well plate, 20 μL of cell/hydrogel was added (1:1 ratio of solutions A and B). The cell proliferation pattern of F3-effluc cells was compared in the soft 1,800 Pa hydrogel (GPT 1.8 K) and the stiff 5,800 Pa hydrogel (GPT 5.8 K). F3-effluc cells proliferated inside GPT 1.8 K over time, and cells started to migrate out from hydrogel mixture on day 4. Neurosphere-like stem cell clusters were also found on day 4. Scale bar = 10 μm. The arrow represents boundary between the bottom of the well plate and cell/hydrogel mixture. (b) In contrast, F3-effluc cells in the stiff GPT 5.8 K proliferated up to 8 day with lower degree than in the soft GPT 1.8 K. Scale bar = 10 μm.