Active Adaptive Materials Design Inspired by Cell Mechanics

控制形状和运动的能力是生命的一个关键特征，从柔软的水母在小裂缝中航行到我们自己的发育，以及我们许多组织在受损后再生和愈合的能力。整个组织和动物的这些能力是在我们身体中单个细胞的尺度上编码的，其尺度与人类头发的宽度相似。在每个细胞内，生物材料构建了机器和材料，使单个细胞能够爬行，根据提示发生变化并构建多细胞组织。许多生物分子是将化学能转化为机械能的分子马达，就像汽车将汽油转化为运动一样。其他分子对这些力作出反应，以控制材料的组装和刚性。在这项提议中，研究人员将使用分子工程来制造合成分子，目的是发现细胞内发现的材料的特性，特别是那些允许它们随时间变化的特性。这项工作将使新型材料能够重现活细胞的行为，包括定向运动和分裂。这种跨学科的材料科学研究将开发工具和知识，也将影响凝聚态物理，生物化学和细胞生物学领域。该项目还将继续努力提高STEM学员的多样性。材料科学的一个前沿是构建自主的、力敏感的材料，这种材料允许相同类型的复杂机械化学机器，使生物体能够运动、生长和分裂。这些材料利用生物分子的酶活性来实现时空调节的力产生（驱动）和机械反应。本提案的科学目标是阐明其驱动和形状可重新编程的软生物聚合物材料的设计原则。活细胞的形状和运动是由肌动蛋白细胞骨架控制的，这是一种复合生物聚合物网络，可以产生可变的力，其粘弹性是动态调节的。这项工作将在体外重建这些材料，开发优化分子控制的分子工程方法和控制和研究其流变反应的方法。有了这些新工具，pi将专注于三个目标：(1)展示对活性材料训练规则的控制，(2)实现在驱动和材料响应之间具有反馈的材料，(3)生成可编程的形态发生材料。这一发现将使软材料在传感、驱动和变形方面具有新的功能，可以广泛应用，包括实现微米级软机器人、传感器和材料。虽然这项研究的重点是基础材料科学，但它将有可能促进对活细胞生理过程的机械调节的理解。这种跨学科的材料科学研究将开发工具和知识，也将影响凝聚态物理，生物化学和细胞生物学领域。该项目还将继续努力提高STEM学员的多样性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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 SummaryThe ability to control shape and motion is a key feature of life, from soft jellyfish navigating small crevices to our own development and the ability of many of our tissues to regenerate and heal after being damaged. These capabilities of whole tissue and animals are encoded at the scale of individual cells in our body, at scales similar to that of a width of a human hair. Within each cell, biological materials construct the machines and materials that enable individual cells to crawl, change in response to cues and build multi-cellular tissue. Many of the biological molecules are molecular motors that convert chemical energy into mechanical work, just like a car converts gasoline to motion. Other molecules respond to these forces to control material assembly and rigidity. In this proposal, the investigators will use molecular engineering to create synthetic molecules with the goal to discover the properties of materials found within cells, especially those that allow them to change over time. This work will enable new classes of materials that can recapitulate behaviors of living cells, including directed motion and division. This interdisciplinary materials science research will develop tools and knowledge that will also impact fields of condensed matter physics, biochemistry and cell biology. The project will also continue efforts to improve the diversity of STEM trainees. Technical SummaryA frontier in materials science is to construct autonomous, force-sensitive materials that allow for the same types of complicated mechanochemical machines that enable living organism locomotion, growth and division. Such materials harness enzymatic activities of biomolecules to enable force-generation (actuation) and mechanical response that is spatiotemporally regulated. The scientific goal of this proposal is to elucidate design principles of soft biopolymer materials whose actuation and shape are reprogrammable. The shape and locomotion of living cells is controlled by the actin cytoskeleton, composite biopolymer networks that generate variable forces and whose viscoelasticity is dynamically regulated. This work will reconstitute these materials in vitro, developing both molecular engineering approaches to optimize molecular control and methodologies to control and study their rheological response. With these novel tools, the PIs will focus on three objectives: (1) To demonstrate control over training rules in active materials, (2) To realize a material with feedback between actuation and material response, (3) To generate programmable morphogenetic materials. The findings will enable soft materials with new functionalities in sensing, actuation and shapeshifting which can be broadly applied, including for the realization of micrometer-scale soft robotics, sensors and materials. While the research is focused on fundamental materials science, it will have potential for advancing the understanding of mechanical regulation of physiological processes in living cells. This interdisciplinary materials science research will develop tools and knowledge that will also impact fields of condensed matter physics, biochemistry and cell biology. The project will also continue efforts to improve the diversity of STEM trainees.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.