title: Reduction of viscosity in suspension of swimming bacteria.
abstract: Measurements of the shear viscosity in suspensions of swimming Bacillus subtilis in free-standing liquid films have revealed that the viscosity can decrease by up to a factor of 7 compared to the viscosity of the same liquid without bacteria or with nonmotile bacteria. The reduction in viscosity is observed in two complementary experiments: one studying the decay of a large vortex induced by a moving probe and another measuring the viscous torque on a rotating magnetic particle immersed in the film. The viscosity depends on the concentration and swimming speed of the bacteria.
authors.affiliation: Illinois Institute of Technology, 3101 South Dearborn Street, Chicago, Illinois 60616, USA.
authors.forename: Andrey
authors.initials: A
authors.lastname: Sokolov
authors.forename: Igor S
authors.initials: IS
authors.lastname: Aranson
mesh_terms: D001412:Bacillus subtilis / Q000502:physiology*; D003198:Computer Simulation; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D012212:Rheology; D014783:Viscosity