Presenter(s): Matthew Kafker—Physics, Mathematics
Faculty Mentor(s): Tristan Ursell
Session: Prerecorded Poster Presentation
Many species of bacteria navigate complex and heterogeneous environments to search for metabolic resources and avoid toxins . Common among such complexities is steric structure—solid objects whose surface curvature alters bacterial trajectories upon impact . In previous experiments, we characterized scattering of bacteria from vertical pillars of different radii, which provides the basis for understanding how impact with a solid, curved object alters bacterial motion . However, it remains poorly understood how multiple interactions affect bacterial trajectories and whether distinct object curvatures or length-scales of separation between steric objects have qualitatively distinct effects on bacterial motion . We address this question using agent-based computer simulations of cells moving within 2D environments . Each environment presents simulated cells with steric objects (i .e . circular pillars) of radius 8 .3μm and a controlled separation between pillars of L μm, where L is a parameter of the simulation . Cells then diffuse through this environment, scattering with pillars they encounter . By measuring the mean squared displacement (MSD) of the ensemble of trajectories in time for different values of L, we are able to quantify precisely how the length-scales of separation between steric structures affect bacterial trajectories . These MSD measurements will also allow us to compare our results with future experimental work . Ultimately, we hope that our results may contribute to a more realistic model of the behavior of motile cells in natural environments such as soils or a mammalian gut .