Fig. 1.

Engineering hydrogels to present extracellular signals to cells. Hydrogels consist of polymer networks in which polymer composition (natural, synthetic or hybrid polymers), polymer crosslinking (covalent or physical) and network degradation (user-mediated and cell-mediated) can be tuned. In addition, biological signals may be introduced as ligands to promote cell adhesion or as soluble factors. Cells interface with hydrogels either through seeding atop (2D) or being encapsulated within (3D).