The invention relates to a method for influencing living cells through cell-surface interaction where, for the cell-surface interaction, bioactive material is applied to magnetic carrier material, then this magnetic carrier material is applied to a magnetic carrier substrate, and this carrier substrate is combined with the living cells. The magnetic domain arrangement in the substrate can be altered by means of an external magnetic field in such a way that the structure formed by the magnetic carrier material is likewise changed. An in vitro alteration of the structure of the substrate is thus possible.