Design and Optimization of Microdevices to Study the Geometrical and Mechanical Control of Microtissue Morphogenesis
Tissue morphogenesis during embryo development and engineered tissue formation is driven by the interaction between cell generated contraction forces and the mechanical boundary condition that resists the contraction. During this process, cells remodel the extra-cellular matrix (ECM), leading to changes in the tissue morphology and structure. Existing engineering approaches to manipulate cellular mechanical environment such as 2D and 3D hydrogels with tunable stiffness do not allow substantial remodeling of the ECM, thus have limited capability to model in vivo tissue morphogenesis. In this thesis, various types of micropost arrays were developed to allow self-assembly of microtissue through cell driven compaction of a cell-ECM mixture. The micropost array both provides mechanical boundary condition to guide the formation of microtissue and acts as force sensors to report spatially-resolved in-situ contraction forces in the microtissue. Current thesis focused on the optimization of the design parameters of the micropost array such as the post array pattern and individual micropost geometry. Cell seedings were performed to test the impacts of varied designed parameters on the microtissue morphology and structure. These findings can be used as design guidelines for the future development of the micropost array system.