Abstract: The present invention relates to a microfluidic device for creating within a cell assembly a cell-free area, comprising at least one cell chamber, wherein the at least one cell chamber comprises: —a fluid inlet for introducing fluid into the cell chamber, —a first area, —a second area, —at least one mechanical excluding means for excluding cells from the first area of the chamber and being operable between an excluding position and a releasing position optionally via an actuation line, wherein the second area of the cell chamber is outside of the operation range of the mechanical excluding means.