Nanotechnologies enable to control and/or tailor steric, electric, and hydrodynamic interactions in confined flows, showing great promises to engineer new molecular biology assays. For instance the conformation of single DNA can be manipulated according to rational rules determined by the geometry of nanochannels [1]:steric constraints tend to align the molecule along the channel. We recently showed that the degee of elongation could be enhanced using hydrodynamics actuation [2], due to centripetal forces induced by shear flows. We now investigate this concept further by monitoring the migration of DNA molecules in slit-channels, and demonstrate that size-dependent migration can be achieved with no separation matrix using combined electro-hydrodynamic actuation [3]. We will show that this separation technology outperforms current separation techniques.