Many living systems, such as bacteria or eukaryotic cells, utilize self-propulsion to enhance transport, find nutrients, or avoid threats. However, cells often inhabit complex and heterogeneous spaces--e.g. gels and tissues in the body, or soil sediments in the environment--that impede rapid transport. Additionally, many biologically and industrially relevant complex materials are opaque and difficult to characterize, indicating the need for adequate computational and analytical models to guide experimental efforts. 

 

In this talk, I will utilize theory and simulation to study the structure and motion of microscopic self-propelled (or active) species in confinement, including bacteria, synthetic swimmers, and cytoskeletal filaments. Active particles accumulate along boundaries due to their self-propulsion, even in the absence of attractive interactions. This mechanism traps the active particles at regions of high concavity, coupling the diffusivity of the swimmer to the microstructure of the confining walls. I shall then extend these results to study the transport of anisotropic active particles (like cytoskeletal filaments or rod-shaped bacteria) in the presence of soft confinement. I will show that the transport of anisotropic swimmers can be controlled (and even enhanced) by patterning the surface topography. The results and design principles developed in this work are relevant in the study of cell transport and in the design of novel lab-on-a-chip devices.