Novel approaches to localization of cytoskeletal proteins and quantification of cell-driven mechanics in three-dimensional model tissue constructs

In a cell-populated collagen gel, intrinsic fiber structure visible through Differential Interference Contrast (DIC) microscopy can provide markers for an in situ strain gauge to quantify cell-gel mechanics, while optical sections of fluorescent protein distribution capture cytoskeletal kinematics.; Mechanics quantification can be derived automatically from timelapse DIC images using a Deformation Quantification and Analysis (DQA) software package accessible via the Internet at dga.web.cmu.edu. Fibroblast contractile machinery was observed to function entirely within pseudopods, while GFP-alpha-actinin concentrated in pseudopod tips and cortex. Complex strain patterns around individual cells showed instances of both elastic and inelastic strain transmission suggesting a role in observed long-range alignment of cells.