The invention relates to a method and a sample separation device (400) for the separation of material from a region of interest, the “sample-ROI” (RS), in a biological sample (11). An embodiment of the invention comprises the application of a structured cover sheet (20) that has an aperture (24) at the sample-ROI to the sample (11). Sample material can then selectively be removed from the sample-ROI through the aperture (24) in the cover sheet. The cover sheet (20) may for example be a tape with an adhesive on one side. The aperture (24) in the cover sheet (20) may automatically be cut out after the selection of a region of interest in a (microscopic) image (I) of the sample. Alternatively, the structured cover sheet (20) maybe produced by printing or plotting. Moreover, sample material may preferably be removed by lysing and may further be subjected to molecular diagnostics (MDx).