Tuning stiffness of cell-laden hydrogel via host-guest interactions.

We report a dynamic hydrogel system with on-demand tunable matrix stiffness. The hydrogels are formed by thiol-allylether photo-click reaction using thiolated poly(vinyl alcohol) (TPVA), 4-arm poly(ethylene glycol)-allylether (PEG4AE), and mono-functional β-cyclodextrin-allylether (βCDAE). Adamantane-functionalized 4-arm PEG (PEG4AD) is used to stiffen hydrogels, whereas unmodified βCD is used to induce gel softening. The stiffening and softening processes are fully reversible and these hydrogels are ideal for investigating the effect of matrix mechanics on cell fate processes.