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.
