Fig. 1. Micropillar and microwell high-throughput culture system.

(A) A micropillar chip with cells suspended in a 3D hydrogel is stamped to a complementary microwell chip containing isolated media conditions to generate 532 independent microenvironments. One hundred nanoliters of hPSCs suspended in a hydrogel is automatically dispensed onto the micropillars, and 800 nl of media is automatically dispensed into the microwells by a robotic liquid handling robot programmed to dispense in custom patterns. The independent substrate for cells and media enables screens of combinations of soluble cues at various dosages and timings. Scale bar, 1 mm. (B) Timeline of exogenous signals for in vitro 3D OPC differentiation from hPSCs and anticipated cellular marker expression along various differentiation stages.