We present an active mixer based on the creation of virtual source-sink pairs in a polydimethylsiloxane (PDMS) chip. Perfect mixing is achieved in only a sub-second time interval for a compact 5 μL mixing volume. This excellent performance is achieved thanks to the implementation of co-rotating vortices inside the mixing chamber by using micro-plumbing technology. A DNA isolation and purification protocol using magnetic beads in the mixing chamber is per-formed on-chip, showing the enhanced DNA binding performance due to active mixing.