CAREER: Microorganisms swimming around microstructural heterogeneity

1252182 Fu所提出的工作的目标是获得对能动微生物（例如细菌）如何能够在复杂的生物环境（例如身体组织或粘液）中移动的基本理解，所述复杂的生物环境通常具有与微生物相似大小的微观结构特征。为了正确研究这些微结构特征对游动微生物的影响，将采用能够计算复杂几何形状周围流动的数值计算。这些计算还将能够研究微结构和游泳微生物的灵活性以及这种灵活性对游泳的影响。在过去，大多数理论研究游泳在这样复杂的环境中只处理的微观结构在平均意义上，这些研究还没有能够确定什么环境属性控制游泳行为。预计将微结构明确地视为移动物体将使人们了解哪些特征促进或阻碍通过这些环境的运动。通过数值计算获得的结果将揭示微观结构对游泳的影响的物理机制，并与不明确处理微观结构的调查结果进行比较。微生物在微结构环境中的运动和推进影响感染，医疗保健和生态。例如，粘液的微观结构可以充当感染的屏障;这项研究可能会找到改变微观结构以阻止感染的方法。需要了解组织渗透，以设计能够将药物精确递送到癌症肿瘤等靶组织的微型机器人，避免对其他组织产生副作用。海洋生物的分泌物可以形成一个微结构网络;了解这个网络对游泳微生物的影响可能会改变对微生物觅食效率的估计，这会影响碳循环速率，从而影响全球气候。在环境方面，可以阻碍细菌在多孔土壤中的分散，以防止水污染，或者加强细菌在多孔土壤中的分散，以促进污染物的生物修复。最后，拟议的工作还包含一个教育部分，旨在创建“像微生物一样移动”，这是一个微尺度微生物运动的力反馈模拟。它将为公众和K-12学生提供微生物如何游泳的实践演示，并解释微生物运动对日常生活的影响。

1252182FuThe goal of the proposed work is to obtain a fundamental understanding of how motile microorganisms, such as bacteria, are able to move through complex biological environments, such as bodily tissues or mucus, which often have microstructural features of similar size as the microorganisms. To properly study the effect of these microstructural features on swimming microorganisms, numerical computations capable of calculating the flows around complex geometries will be employed. These computations will also be able to study the flexibility of the microstructures and the swimming microorganisms and the effects of this flexibility on swimming. In the past, most theoretical investigations into swimming in such complex environments have only treated the microstructure in an average sense; these studies have not been able to determine what environmental properties control swimming behavior. It is expected that treating the microstructure explicitly as moving objects will give insight into what features promote or hinder movement through these environments. The results obtained through the numerical computations will expose the physical mechanisms of microstructural influence on swimming and be compared to results from investigations that do not treat the microstructure explicitly. Microorganism locomotion and propulsion in environments with microstructure affects infection, healthcare, and ecology. As examples, the microstructure of mucus can act as a barrier in infection; the research may lead to ways to alter the microstructure to hinder infection. Understanding tissue penetration is needed to design microrobots capable of precise delivery of drugs to targeted tissues such as cancer tumors, avoiding side effects in other tissues. Ecologically, the secretions of marine organisms can form a microstructural network; understanding the effects of this network on swimming microorganisms may alter estimates of microbial foraging efficiency, which affects carbon recycling rates and hence the global climate. Environmentally, bacterial dispersion in porous soils can be hindered to prevent water contamination or enhanced to promote bioremediation of pollutants. Finally, the proposed work also contains an educational component which aims to create "Move Like a Microbe," a force-feedback simulation of microscale microbial locomotion. It will bring the proposed research to life for the public and K-12 students by providing a hands-on demonstration of how microorganisms are able to swim, and explain the consequences of microbial locomotion to everyday life.