Escape problem of magnetotactic bacteria - Physiological magnetic field strength help magnetotactic bacteria navigate in simulated sediments

Here, we produced microfluidic channels that contained sediment-mimicking obstacles to study swimming of magnetotactic bacteria in a near-realistic environment that resembles their natural habitat. Magnetotactic bacteria are microorganisms that form chains of nanomagnets and that orient in the Earth magnetic field.

The obstacles were produced based on micro-computer tomography reconstructions of bacteria-rich sediment samples. We characterized the swimming of magnetotactic bacteria through these channels and found that swimming throughput was highest for physiological magnetic fields. This observation was confirmed by extensive computer simulations using an active Brownian particle model, which were parameterized based on experimental trajectories, in particular with the trajectories near the sedimentmimicking obstacles, from which the interactions of the swimming bacteria with the obstacles were determined.