Controlled Stem Cell Heterogeneous Differentiation On Shape Memory Hydrogel Surface

A novel double-ion-triggered shape memory hydrogel was developed.Introducing and removing two types of divalent ions could contribute to reversibledissociation/reassociation of dipole-dipole pairings andion-complexation/decomplexation, thereby giving rise to multiple shape memoryeffect. The shape memory effect reported here allows for uniquely tuning thedifferentiation behavior of stem cells. During fixation of temporary shape bydipole-dipole interaction and calcium-chelation, hMSCs were seeded on the hydrogelsurface; after extracting Ca2+, the hydrogel-hMSCs construct could automaticallyconvert into a cubic box where hMSCs were shown to exhibit heterogeneousdifferentiation behavior at different growth positions. The "up-side-down" growthposition promoted the process of adipogenesis while the "wall-hanging" growthcondition favored the process of osteogenesis. Our finding will not only provide anew approach to fabricating one-of-a-kind shape memory hydrogel tissue engineeringscaffold, but also benefit the fundamental understanding of the differentiationbehavior of stem cells in complex geometrical space.