Fig. 2.

Various design strategies implemented to allow spatial patterning and co-culture of cells in microfluidic platforms: (a) Capillary pinning based: (i) Microposts based, (ii) Phaseguides based. (b) Sacrificial or non-sacrificial materials based strategy: (i) 3D bioprinting based strategy wherein hollow space is created inside hydrogel by removal of bioprinted sacrificial material, (ii) Needle based strategy wherein hollow space is created inside the hydrogel. In both (i) and (ii) the hydrogel can contain cells and hollow space can be endothelialized or epithelialized. (c) Milli-compartments or micro-compartments based strategy: (i) Transwell-based dynamic organ-on-chips, (ii) 3D scaffold-based dynamic organ-on-chips. (d) Membrane-based compartmentalization strategy. Figure (c–i) is adapted under terms of the CC-BY license from Ref. [75] Copyright 2022, Springer.