Rigid Body Dynamics of Motile Bacteria Near Surfaces*

Motile bacteria in their natural environment commonly interact with surfaces. Using total internal reflection fluorescence microscopy, we record the trajectories of Escherichia coli cells swimming near surfaces. By fitting ellipsoids to the fluorescent intensity profiles of the bacteria via a novel method, we extract their translational and rotational dynamics. We present results from our analysis for experiments with both wild-type and smooth-swimming E. coli strains.