The invention concerns the domains of materials science and medicine and relates to a method such as can be applied to in vivo or in vitro fertilization, for instance. The problem addressed by the present invention is that of specifying a method with which the activity and controlled mobility of motile cells is improved and the absorption of materials alien to the cell is prevented as far as possible. The problem is solved by a method in which one or more motile cells are introduced into or attached to one or a plurality of magnetic particles, and subsequently the magnetic particles with the motile cells introduced into them or attached to them are moved in a directional manner by the application of an external magnetic field. The problem is further solved by the use of the method for the controlled movement of motile cells in liquid or gaseous media in the body of a mammal or human being.