Real time remodeling of cellular morphology using optical imprinting of cell-culture substrates

Development of materials that can dynamically alter the topographic experience of cultured cells is key to accurately modeling in vivo processes such as tissue development and repair. Current technologies have largely focused on smart substrate materials that can be programmed to undergo topographical transformations in the presence of adhered cells, but such materials provide limited spatiotemporal resolution and generally are triggered by undesirable changes to environmental conditions. Here, we present an approach for investigating cellular responses to dynamic topographical cues in which multiphoton photochemistry is used to remotely imprint a substrate with arbitrary topographical patterns in real time (i.e., in the presence of adherent cells). In these studies, fibroblastic NIH3T3 cells were plated on a planar protein hydrogel substrate, where they generally established stereotypical polygonal morphology before the underlying substrate was dynamically transformed to a grooved topography. Elongation and alignment of cells exposed to low-micrometer-pitch grooves imprinted in this manner occurred less rapidly than for cells directly deposited on substrates having pre-formed grooves. Further, cell alignment on dynamically imprinted grooves was notably delayed relative to elongation, suggesting that the structural attributes of a cell at the time it first experiences a grooved topography may differentially influence these two processes. This minimally invasive approach for subjecting cells to dynamic topographical experiences represents a versatile means to model evolving conditions within in vivo systems and to systematically explore mechanisms of cellular morphology and behavior.