Set for applying a flat, flexible two-dimensional thin-film strip into living tissue, in particular brain, is described. It comprises: the thin-film strip (6) itself to be applied, an application tool (7) removable and mechanically connectable to the thin-film strip (6) by means of a coupling device (8, 13 15, 16, 18 23, 29, 36, 37), wherein after application of the thin-film strip (6) in situ the application tool (7) is removable from the tissue without residue by mechanically disengaging the coupling device (8, 13 15, 16, 18 23, 29, 36, 37) itself thereby leaving the thin-film strip (6) behind.