(702g) Invited Speaker: Engineering Microenvironments for Probing and Manipulating Cellular Mechanical Activities

Cellular mechanical activities play a critical role in both physiological and pathological processes including cancer invasion. To understand and control these activities, conventional biological approaches must be combined with approaches that manipulate physical properties of the microenvironment. We have applied materials and microfabrication approaches to impose defined size, shape, stiffness, migration path, or mechanical forces on single cells and cell collectives. This combined approach has revealed profound differences between migrating and stationary cells, which may control important properties such as differentiation. We have also designed micropatterns to facilitate the encounter between migrating cells, which then led to the discovery that cell migration is affected by a combination of contact inhibition and contact following, depending on the site of cell-cell contact. In addition, micropatterning has allowed us to obtain defined collectives of epithelial cells, as migrating trains of 5-6 cells with a uniform polarity. We found that contact following, in conjunction with contact inhibition and cell-cell adhesion, represents a fundamental mechanism for collective migration. We have further designed an on-stage stretching device for characterizing the responses of single cells and cell collectives within confined domains to imposed strains. The combination of biological, materials, and mechanical approaches is expected to continue to uncover important functional aspects critical to a wide range of medical applications including cancer treatment and tissue regeneration.