Bacterial chemotaxis in confining geometries

Many bacteria have evolved the ability to move actively through their environment, and also to direct this motion towards beneficial substances or away from harmful ones, an ability known as chemotaxis. It has been suggested that in some conditions such chemicals may be secreted by bacteria themselves, introducing the potential for chemotaxis to be used for inter-bacterial signalling and collective motion. It has also been shown that non-uniform distributions of bacteria can be produced through control of the environmental topology. In this talk I will address the behaviour arising from the interplay of these two phenomena. I will introduce a theoretical model of chemotaxis, and show results of simulations with the aim of reproducing experimental data. These suggest that the interaction of bacteria with planar surfaces, coupled with chemotaxis towards a self-secreted chemoattractant, may explain spontaneous clustering in chemically uniform environments. This has implications for the control of bacterial populations via shaping of environmental geometry, and may provide insight into how bacteria can achieve a critical density for virulence through chemical signalling.