Collaborative Research: Bacterial Flagellar Forests: Designing a Biomaterial for Bio-Enabled Sensing and Actuation

材料研究部的生物材料项目资助了德雷克塞尔大学和内华达大学雷诺大学的研究人员的合作努力，将细菌鞭毛作为能够感知和驱动的活性生物材料的组成部分进行研究。这个合作项目是由化学、生物工程、环境和运输系统部门的纳米生物传感计划共同资助的。细菌鞭毛是由鞭毛蛋白亚基组成的螺旋自组装结构。鞭毛的一个关键特性是多态转化，它依赖于外界刺激，包括温度、离子强度、pH、光强迫，可能还取决于特定配体的浓度。但是，诱导转化所需的刺激的具体水平还没有很好地确定。这项拟议工作的目标是创建一个鞭毛林，由系在底物上的鞭毛阵列组成。作为对外界刺激的反应，鞭毛的多态变化与集体鞭毛的动态相结合，将使鞭毛林能够自主地感知和启动对环境的反应。为了实现这一目标，研究人员将：(1)通过收集细丝形成有序的阵列，将其拴在由外部旋转磁场共同驱动的衬底上的磁电机上，来创建鞭毛林；(2)表征单个鞭毛对热、化学、机械和光学环境刺激的反应；以及(3)了解单个鞭毛如何相互作用来创造鞭毛森林生物材料的集体反应。这一合作项目的更广泛的科学影响是，了解生物系统中的宏观自主行为是如何由纳米级的电荷和质量传输控制的，而纳米级的电荷和质量传输又是由大量聚合物生物分子的动态响应控制的。该项目的教育目标是向更年轻、更广泛的受众有效地交流尖端研究，并激励他们朝着获得STEM领域学位的目标前进。在工程系统中使用生物纳米材料是理解生物世界如何在纳米尺度上进化的关键一步，以及科学家和工程师如何使用现代组装和合成技术改进自然。“智能”系统的设计可以利用材料，这些材料可以自主地对周围环境的变化做出反应。此外，这项工作包括为研究生和本科生提供广泛的培训内容，为他们在具有全面生物和工程背景的学术界和工业界的职业生涯做好准备。在整个项目中，私人投资机构将继续招聘和指导任职人数不足的群体在STEM领域工作。这项研究将通过强有力的外展努力向公众传播。在德雷克塞尔大学，INSPIRE学院将为高中师生带来尖端的生物材料和生物制造。在雷诺的内华达大学，“像微生物一样移动”计划将通过大学的“工程师日”、“工程夏令营”和“移动工程教育实验室”推广计划，为K-12学生和公众带来这项研究的生命。此外，将利用YouTube等网络和社交媒体传播科学发现，并使科学对K-12学生、教师和普通公众更具吸引力。

The Biomaterials program in the Division of Materials Research funds the collaborative efforts of researchers at Drexel University and University of Nevada Reno to study bacterial flagella as a component of an active biomaterial that are capable of sensing and actuation. This collaborative project is cofunded by the Nano-Biosensing program in the Division of Chemical, Bioengineering, Environmental, and Transport Systems. Bacterial flagella are helical self-assembled structures composed of flagellin subunits. Polymorphic transformations, a key property of flagella, depend on external stimuli including temperature, ionic strength, pH, optical forcing, and possibly by concentration of specific ligands. But the specific levels of stimuli needed to induce transformations have not been well-determined. The goal of the proposed work is to create a flagellar forest consisting of an array of flagella tethered to a substrate. In response to external stimuli, flagellar polymorphic transformations coupled to collective flagellar dynamics will enable the flagellar forest to sense and actuate autonomously in response to the environment. To accomplish the goal, the researchers will: (1) create flagellar forests by gathering filaments into ordered arrays tethered to magnetic motors on a substrate which are actuated by an external rotating magnetic field en masse; (2) characterize the response of individual flagella to thermal, chemical, mechanical, and optical environmental stimuli; and (3) understand how individual flagella interact to create the collective response of the flagellar forest biomaterial. The broader scientific impact of this collaborative project is in developing an understanding how macroscale autonomic behavior in biological systems that is controlled by charge and mass transport at the nanoscale, which, in turn, is controlled by the dynamic response of a vast array of polymeric biomolecules. The educational goal of this project is to effectively communicate cutting-edge research to younger and broader audiences and inspire them toward the goal of obtaining a degree in STEM fields.The use of biological nanomaterials in an engineered system presents a critical step toward understanding how the biological world has evolved at the nanoscale, as well as how scientists and engineers can improve upon nature using modern assembly and synthesis techniques. The design of "smart" systems can take advantage of materials which can respond autonomously to changes in their surroundings. In addition, the work includes an extensive training component for graduate and undergraduate students, preparing them for careers in academia and industry with a comprehensive background in biology and engineering. Throughout the project, the PIs will continue to recruit and mentor underrepresented groups to work in STEM fields. The research will be communicated to the public through strong outreach efforts. At Drexel University, the INSPIRE academy will bring cutting-edge bionanomaterials and biomanufacturing to high school teachers and students. At the University of Nevada, Reno, the "Move Like a Microbe" program will bring this research to life for K-12 students and the public through University's "Engineer's Day", "Summer Engineering Camp", and "Mobile Engineering Education Lab" outreach programs. Additionally, web-based and social media outlets such as YouTube will be utilized to disseminate the scientific discoveries, and to make science more appealing to K-12 students, teachers and the general public.