Dissertation Award in Statistical and Nonlinear Physics Talk: Life in Suspense: Particle dynamics in suspensions of swimming bacteria

Cells and microorganisms move in diverse environments that range from pond and ocean water to complex biological fluids, such as mucus. These environments frequently contain passive particles, such as macromolecules, flexible polymers, or colloids, which can influence cell motility and behavior. Interactions between cells and particles underlie many aspects of medicine, biology, and engineering, including the spread of bacterial infections, the formation of biofilms, and the design of swimming micro-robots. Identifying means to relate the microstructural features of the swimmer to macrostructural properties and bulk phenomena of the fluid would yield ways to control, manipulate, and direct biological systems. In this talk, I will explore the use of colloidal particles and polymer molecules to experimentally probe the emergent non-linear flows in suspensions and swarms of bacteria. The results identify new avenues of transport and highlight how active bacterial fluids differ from their passive counterparts. I will discuss applications to particle sedimentation and boundary propagation in microbial environments.