Engineering Cytoskeletal Active Materials

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Non-technical Abstract Living organisms spontaneously execute complex shape changes and motions. These properties are enabled by the unique materials within biological organisms. Many of the biological molecules, some of which have the capability to act as molecular motors to convert chemical energy into mechanical work. When these motors work in concert, they build fluids and solids with internal forces that spontaneously flow and change shape. In this proposal, the investigators will use molecular engineering to create synthetic molecular motors not found in nature with the goal to discover new types of behaviors and control over active materials. This work will enable new classes of materials that can recapitulate behaviors of living cells, including directed motion and division.Technical AbstractThe scientific goal of this proposal is to engineer active soft materials whose structure, mechanics and transport properties can be controlled by tuning the activity of constituents. Active materials constitute a broad class of systems that contain distributed stress-generating elements which underlie their spontaneous motion, pattern formation and shape changes. Within living cells, ensembles of mechanochemically active proteins support morphogenic processes at cellular and tissue scales with precise spatiotemporal control. A common structural motif of cytoskeletal materials are collections of biopolymers and molecular motors (e.g. actin filaments with myosin motors and microtubules with kinesin motors). The proposed work will exploit recent advances in molecular motor engineering to construct active materials with controllable sources of active stress that can be spatiotemporally modified. This will enable understanding of how molecular-scale properties of mechanoenzymes regulate the emergent biophysical and material behaviors of the resultant contractile gels and extensile fluids. The work proposed here will develop versatile new experimental platforms to engineer and study spatially structured active materials. Applications of this work is envisioned to construct new classes of autonomous and force-sensitive materials. Moreover, these studies will shed light on the materials design principles properties that underlie cell motility, division and shape. The broader impacts of this work will create new knowledge at the interface between materials science, synthetic biology and cell biology, train an interdisciplinary work force and improve diversity in the STEM workforce.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.