Directing cell migration on flat substrates and in confinement with microfabrication and microfluidics.

Cell motility has been mainly characterized in vitro through the motion of cells on 2D flat Petri dishes, and in Boyden chambers with the passage of cells through sub-cellular sized cavities. These experimental conditions have contributed to understand important features, but these artificial designs can prevent elucidation of mechanisms involved in guiding cell migration in vivo. In this context, microfabrication and microfluidics have provided unprecedented tools to design new assays with local controls in two and three dimensions. Single cells are surrounded by specific environments at a scale where cellular organelles like the nucleus, the cortex, and protrusions can be probed locally in time and in space. Here, we report methods to direct cell motion with emphasis on micro-contact printing for 2D cell migration, and ratchetaxis/chemotaxis in 3D confinements. While sharing similarities, both environments generate distinct experimental issues and questions with potential relevance for in vivo situations.