Locomotion and Transport in a Liquid Crystal

本研究的目的是探讨微生物在液晶环境中游动的基本原理。游泳和微生物群是当前相当感兴趣的话题，在比水更复杂的流体中游泳的情况下，还有很多研究有待完成。这项工作的结果将加深我们对微生物在复杂但非常相关的系统（如粘液和生物膜）中的行为的理解。PI将继续参与教师研究经验计划，该计划邀请当地学校的K-12教师到布朗大学校园参加实验室研究和课程开发项目，并在布朗大学暑期高中计划中就运动和液晶物理进行讲座和示范。PI还将为普罗维登斯课后联盟（PASA）提供讲座和讨论，这是一个为高中生提供更多学习机会的地方组织。本研究的目的是为理解微生物在液晶溶液中的游动提供理论框架。这些液晶溶液是研究更复杂的各向异性生物系统的模型系统，但作为一种操纵活性胶体粒子的手段，它们本身也很有趣。虽然牛顿流体（如水）中微观游泳者之间的流体动力学相互作用受到了很多关注，但细菌通常在充满聚合物的环境中定居。由于这些聚合物通常呈棒状排列，因此这些环境通常是各向异性的。例如，细胞外DNA在生物膜中形成平行束，并且观察到细菌优先沿着排列方向游动。此外，几个实验小组最近开始研究在无毒合成液晶溶液中游动的细菌。该提案正是在解决这个问题，即发展一种理论来描述实验观察到的现象。

The goal of the proposed study is to investigate the fundamentals of swimming of microorganisms in liquid crystal environments. Swimming and swarming of microorganisms is a topic of considerable current interest, with a lot of research left to be done in the case of swimming in fluids that are more complex than water. Results of this work will deepen our understanding of the behavior of microorganisms in complex yet very relevant systems, such as mucus and biofilms. The PI will continue to participate in the Research Experiences for Teachers program, which invites K-12 teachers from local schools to the Brown campus to participate in laboratory research and course development projects during the summer, and in the Brown University Summer High School program , giving lectures and demonstrations on the physics of locomotion and liquid crystals. The PI will also contribute lectures and discussions to the Providence After School Alliance (PASA), a local organization that provides expanded learning opportunities to high school students.The goal of the proposed research is to provide the theoretical framework for understanding the swimming of microorganisms in liquid crystal solutions. These liquid crystal solutions are model systems for the study of more complicated anisotropic biological systems, but are also interesting in their own right as a means for manipulating active colloidal particles. While the hydrodynamic interactions between microscopic swimmers in Newtonian fluids, such as water, have received a lot of attention, bacteria commonly colonize environments laden with polymers. Since these polymers are typically rod-like and aligned, these environments are often anisotropic. For example, extracellular DNA forms parallel bundles in biofilms, and bacteria have been observed to swim preferentially along the direction of alignment. Furthermore, several experimental groups have recently begun to study swimming bacteria in nontoxic synthetic liquid crystal solutions. The proposal is addressing this issue exactly, the development of a theory that would describe phenomena that are experimentally observed.