Collaborative Research: Enzyme-Powered, Programmable Active Matter

非技术摘要：想象一个世界，在这个世界里，道路可以感觉到它们的损坏并像人类皮肤一样自我修复，或者在这个世界里，森林火灾和山体滑坡等自然灾害可以通过自动改变形状和硬度的材料来防止，或者当服装本身感觉到空气中的病原体时，服装材料会改变它们的孔隙率，成为个人防护装备(PPE)。这些未来主义的想法目前只是科幻小说，但如果我们有任何创造这些令人惊叹的技术的希望，我们需要从今天开始。这一合作项目旨在探索此类应用所需材料的基本基础。具体地说，为了设计任何这样的未来主义设备，我们需要有自我供电的材料，并从耗能的积木分级组装。幸运的是，许多生物系统，如细胞、植物和人类，已经能够感知它们的环境，并通过移动、改变形状或释放化学物质来做出反应。这些生物“系统”的基本构件是酶，这是一种由各种形状和大小的蛋白质组成的纳米机器。为了剖析并开始理解酶是如何使物质充满活力的，我们的团队将使用酶来为新的合成材料提供纳米到微米级的动力。未来，这些纳米级材料可以自行组装，创造出新的更大规模的活性材料。技术摘要：该项目的科学目标是了解以酶为动力的合成活性材料的物理原理。研究团队结合了DNA纳米技术、酶动力学、单颗粒跟踪和敏感力测量方面的专业知识，以实现以下目标：(1)团队使用DNA折纸来设计、创建和表征一套由酶催化驱动的活性颗粒，具有可编程的推进酶的大小、形状、灵活性和位置。这个目标解决了创造新的纳米到中尺度活性粒子的需要，并使用这些粒子来了解控制增强运动性的机制。(2)该团队通过波动光谱、能量耗散以及主动浴推动被动粒子从噪声中提取功的能力来表征由酶驱动的颗粒的主动浴的特性。对单个粒子的运动性和从活性粒子集合中产生的活性涨落的联合研究将揭示丰富的新信息，包括活性粒子增强输运的机制，以及对活性涨落的非平衡统计力学描述。这种方法的重要性在于有可能指定活性粒子的微观细节，如它们的大小、形状和灵活性，然后发现这些属性如何改变单个粒子和集体行为。这项DMR拨款支持研究，以了解由酶驱动的合成活性材料的物理，资金来自数学和物理科学总监材料研究部的凝聚态物质物理(CMP)和生物材料(BMAT)计划。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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:Imagine a world in which roads can sense their damage and repair themselves like human skin, or in which natural disasters such as forest fires and landslides are prevented by materials that change shape and stiffness automatically, or in which clothing materials change their porosity to become personal protective equipment (PPE) when the clothing itself senses airborne pathogens. These futuristic ideas are currently science fiction, but if we have any hope of creating these amazing technologies, we need to begin today. This collaborative project seeks to explore the fundamental underpinnings of the materials needed for such applications. Specifically, in order to design any of these futuristic devices, we need to have materials that are self-powered and assembled hierarchically from energy-using building blocks. Luckily, many biological systems, such as cells, plants, and humans, are already capable of sensing their environment and responding by moving, changing shape, or releasing chemicals. The basic building blocks of these biological “systems” are enzymes, nanoscale machines made of protein that come in a variety of shapes and sizes. In order to dissect and begin to create an understanding of how enzymes can animate matter, our team will use enzymes to power new synthetic materials at the nanoscale to microscale. In the future, these nanoscale materials can be assembled themselves to create new larger scale active materials. Technical Abstract:The scientific objective of this project is to understand the physics of synthetic active materials powered by enzymes. The research team combines expertise in DNA nanotechnology, enzyme kinetics, single-particle tracking, and sensitive force measurements to address the following objectives: (1) The team uses DNA origami to design, create, and characterize a suite of active particles, driven by enzyme catalysis, with programmable size, shape, flexibility, and location of propulsive enzymes. This objective addresses a need to create new nano- to mesoscale active particles and uses these particles to understand the mechanisms governing enhanced motility. (2) The team characterizes the properties of an active bath of enzyme-driven particles via the fluctuation spectrum, dissipation of energy, and the ability of an active bath to propel passive particles to extract work from noise. A combined study of the single-particle motility and the active fluctuations that emerge from collections of active particles will reveal a wealth of new information, including the mechanisms of enhanced transport of active particles, as well as a non-equilibrium statistical mechanical description of active fluctuations. The importance of this approach lies in the potential to specify the microscopic details of active particles, like their size, shape, and flexibility, and then to discover how these attributes alter the single-particle and collective behaviors.This DMR grant supports research to understand the physics of synthetic active materials powered by enzymes with funding from the Condensed Matter Physics (CMP) and Biomaterials (BMAT) Programs in the Division of Materials Research of the Mathematical and Physical Sciences Directorate.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.