The present invention relates to a microfluidic device 100 for the concentration and the lysis of cells 502 or viruses and a method of concentrating and lysing cells 502 or viruses using the microfluidic device 100. The microfluidic device 100 includes: a reaction chamber 202, in which magnetic beads 102 can be accommodated, comprising a plurality of electrodes 20, 20' for generating a non-uniform electric field; a vibrating part 302 for agitating the magnetic beads in the chamber; and a laser source 402 for radiating a laser beam 404 onto the magnetic beads 102 in the reaction chamber 202.