I will present recent results and discuss future directions for numerical
simulations of swimming bacteria and cells in the presence of funnel
geometries. We show that in modeling the bacteria, only a few simple
assumptions, such as run and tumble dynamics combined with a rule for the
motion of bacteria along a wall, are sufficient to produce a rectification or
directed motion of the bacteria. Our simulation results are in excellent
agreement with experiments and open the possibilities for a wealth of new
types of devices such as cell sorting, dynamical self-assembly, rotating
microscopic gears, and enhanced diffusion of asymmetric objects immersed in
bacterial baths. We also discuss how more complex cellular motion could be
modeled and how different methods of cell locomotion could lead to cells moving
in different directions on asymmetric substrates.
