Engineering Cytoskeletal Active Materials

生物体自发地执行复杂的形状变化和运动。这些特性是由生物有机体中的独特材料实现的。 许多生物分子，其中一些具有分子马达的能力，将化学能转化为机械功。 当这些马达协同工作时，它们会产生具有内力的流体和固体，这些流体和固体会自发地流动并改变形状。 在这项提案中，研究人员将使用分子工程来创造自然界中没有发现的合成分子马达，目的是发现新类型的行为和对活性材料的控制。 这项工作将使新的材料类别，可以重演的行为活细胞，包括定向运动和division.Technical AbstractionThe科学目标的建议是工程的活性软材料的结构，力学和运输性能可以通过调整组分的活性控制。活性材料构成了一个广泛的系统类别，包含分布式应力产生元件，这些元件是它们自发运动、图案形成和形状变化的基础。 在活细胞内，机械化学活性蛋白质的集合支持细胞和组织尺度的形态发生过程，具有精确的时空控制。细胞骨架材料的常见结构基序是生物聚合物和分子马达的集合（例如具有肌球蛋白马达的肌动蛋白丝和具有驱动蛋白马达的微管）。 拟议的工作将利用分子马达工程的最新进展，以构建具有可控主动应力源的活性材料，这些主动应力源可以在时空上进行修改。 这将有助于理解机械酶的分子尺度特性如何调节所产生的收缩性凝胶和伸展性流体的新兴生物物理和材料行为。 本文提出的工作将开发多功能的新实验平台，以设计和研究空间结构的活性材料。这项工作的应用被设想为构建新的自主和力敏材料。 此外，这些研究将揭示材料的设计原理，细胞运动，分裂和形状的基础属性。这项工作的广泛影响将在材料科学、合成生物学和细胞生物学之间的界面上创造新的知识，培养跨学科的工作队伍，提高STEM劳动力的多样性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.