2.5. Alginate hydrogel formation

Alginate hydrogels containing hMSCs were made by centrifuging 100,000 cells at 500 × g for 5 min and resuspending them in 10 μl of 1% (w/v) alginate (either with or without RGD) in NaCl (0.9% [w/v] in water). The alginate hydrogels were formed by dispensing the 10 μl droplet into a 100 mM CaCl₂ (Sigma‐Aldrich) bath and allowing it to cross‐link for 5 min. The crosslinking solution was then replaced by growth medium for subsequent culture in non‐adherent cell culture plates (VWR). Phase contrast micrographs of hMSCs encapsulated in alginate hydrogels were taken at days 1 and 14 with a Nikon eclipse TS100 inverted microscope.