A Combinational Effect of "Bulk" and "Surface" Shape-Memory Transitions on the Regulation of Cell Alignment.

A novel shape-memory cell culture platform has been designed that is capable of simultaneously tuning surface topography and dimensionality to manipulate cell alignment. By crosslinking poly(ε-caprolactone) (PCL) macromonomers of precisely designed nanoarchitectures, a shape-memory PCL with switching temperature near body temperature is successfully prepared. The temporary strain-fixed PCLs are prepared by processing through heating, stretching, and cooling about the switching temperature. Temporary nanowrinkles are also formed spontaneously during the strain-fixing process with magnitudes that are dependent on the applied strain. The surface features completely transform from wrinkled to smooth upon shape-memory activation over a narrow temperature range. Shape-memory activation also triggers dimensional deformation in an initial fixed strain-dependent manner. A dynamic cell-orienting study demonstrates that surface topographical changes play a dominant role in cell alignment for samples with lower fixed strain, while dimensional changes play a dominant role in cell alignment for samples with higher fixed strain. The proposed shape-memory cell culture platform will become a powerful tool to investigate the effects of spatiotemporally presented mechanostructural stimuli on cell fate.