Collaborative Research: Theoretical and Experimental Investigation of Synthetic Micro/Nano-Swimmers in Shear-thinning Fluids

合成游泳者是工程微观或纳米级物体，模仿自然微生物如何在其环境中游泳。 可以在生物液体中移动的合成游泳者在药物输送和显微外科手术等生物医学应用中显示出巨大的前景。 这些游泳者在生物医学任务中的成功应用依赖于他们在生物液体（如血液）中移动的能力，这些生物液体具有对周围环境做出反应的复杂和变化的特性。虽然最近有关于这些流体中运动的研究，但关于定向施加的力或其他运动（如摇动和搅动）对游泳的影响，还有很多东西有待了解。 该研究项目旨在量化和阐明复杂（非牛顿）流体特性对合成微型游泳者运动的影响。这些成果将使具有强大游泳能力的微型机器人能够用于下一代医疗保健应用。 该项目将通过高级设计项目和本科生研究参与来整合研究和教育。通过利用现有的大学课程和来自研究项目的新活动，研究人员每年将为大约120名高中生提供外展服务。 该项目还将支持在加州科学中心举办一个名为“吞下一个外科医生”的展览（洛杉矶，CA）为了让普通公众了解设计生物医学微型机器人所面临的挑战和取得的进展，在圣克拉拉大学和加州理工学院的这项合作研究项目中，计算和实验将被用来理解运动在剪切稀化流体和识别有效的策略，以考虑这种非牛顿流体的行为，在设计合成游泳。现有的推进机制可以大致分为从局部化学反应中获取能量的化学动力游泳者和需要外部场驱动的游泳者。在本研究项目中，将研究每个类别的代表性模型系统，以评估剪切稀化流变学对小尺度主要类型合成游泳运动员的影响。理论和实验将使用催化发动机和柔性磁性纳米线推进器，以全面了解不同类型的非牛顿流体行为及其相互作用如何影响小尺度运动。该项目的完成将导致对复杂流体中的流体-结构相互作用和泳动的新的基础知识。这一改进的理解将反过来指导下一代合成游泳者的设计，可以有效地通过生物流体移动。这个奖项反映了NSF的法定使命，并已被认为是值得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的支持。

Synthetic swimmers are engineered microscopic or nanoscopic objects that mimic how natural microorganisms swim through their environment. Synthetic swimmers that can move through biological fluids show great promise in biomedical applications such as drug delivery and microsurgery. Successful applications of these swimmers to biomedical tasks rely on their ability to move through biological fluids, such as blood, with complex and varying properties that respond to their surroundings. While there have been recent studies on the subject of locomotion in these fluids, much remains to be learned about the influence of directional applied forces or other motions such shaking and agitation, on swimming. This research project aims to quantify and elucidate the impacts of complex (non-Newtonian) fluid properties on the locomotion of synthetic micro-swimmers. The outcomes will enable the development of micro-robots with robust swimming capabilities for next generation healthcare applications. The project will integrate research and education through senior design projects and undergraduate research participation. By leveraging existing university programs with new activities derived from the research project, the researchers will provide outreach to approximately 120 high-school students annually. The project will also support an exhibition entitled "Swallowing a Surgeon" at the California Science Center (Los Angeles, CA) in order to expose the general public to the challenges and progress made towards designing biomedical micro-robots.In this collaborative research project between Santa Clara University and the California Institute of Technology, computations and experiments will be used to understand locomotion in shear-thinning fluids and to identify effective strategies to account for this non-Newtonian fluid behavior in the design of synthetic swimmers. Existing propulsion mechanisms can be broadly categorized into chemically-powered swimmers that harvest energy from local chemical reactions, and swimmers that require external fields for actuation. In this research project, representative model systems from each category will be studied to evaluate the impacts of shear-thinning rheology on major types of synthetic swimmers at small scales. Theory and experiments will use catalytic motors and flexible magnetic nanowire propellers to provide a comprehensive understanding of how distinct types of non-Newtonian fluid behaviors and their interactions affect locomotion at small scales. The completion of this project will lead to new fundamental knowledge on fluid-structure interactions and phoretic motion in complex fluids. This improved understanding will in turn guide the design of next-generation synthetic swimmers that can move through biological fluids effectively.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.